w* 


Book  No 


Date  Due 


A  £TUDY 


OF  THE 


HUMAN  BLOOD-VESSELS 


IN   HEALTH  AND   DISEASE 


A  SUPPLEMENT  TO 

"THE  ORIGIN  OF  DISEASE" 


BY/ 

ARTHUR  V.  MEIGS,  M.D. 

PHYSICIAN   TO  THE   PENNSYLVANIA   HOSPITAL 


WITH  ONE  HUNDRED  AND   THREE  ORIGINAL  ILLUSTRATIONS 


PHILADELPHIA  &  LONDON 
J.   B.   LIPPINCOTT    COMPANY 


\MG-  606 


COPYRIGHT,   1907 

BY  J.  B.  LIPPINCOTT  COMPANY 


PREFACE 


IN  the  latter  part  of  the  year  1899  a  fire  destroyed  every  unsold 
copy  of  my  book  on  "  The  Origin  of  Disease."  The  publisher- soon 
afterwards  asked  if  I  would  not  seize  the  opportunity  to  turn  a 
pecuniary  loss  into  an  advantage  by  issuing  a  new  and  perfected  edi- 
tion. This  obliged  me  to  make  an  examination  of  my  work,  and  I 
reached  the  conclusion  that  one  of  the  best  parts  of  it  was  the  chapter 
on  the  blood-vessels,  and  that  it  was  also  the  most  imperfect  and  in- 
complete. When  I  studied  the  subject-matter,  the  origin  of  disease, 
and  the  secondary  subject,  the  disease  of  age,  I  found  I  could  not  add 
much  to  what  had  already  been  set  forth,  but  that  my  descriptions  of 
the  anatomy  and  pathology  of  the  blood-vessels  were  inadequate  and, 
besides,  in  the  interval  since  the  book  was  issued  I  had  accumulated 
new  facts.  These  facts,  however,  were  not  suitable  to  be  incorporated 
with  the  material  treated  under  the  old  title.  Although  the  various 
subjects  discussed  in  "The  Origin  of  Disease  "  are  intimately  related, 
and  although  the  new  material  collected  had  grown  from  the  pursuit 
of  the  same  studies  that  led  to  the  writing  of  my  book,  it  seemed  im- 
possible to  weave  the  new  material  and  the  old  together  in  such  a  way 
as  to  form  a  harmonious  whole.  It  is  not  my  intention  to  claim  that 
my  book  on  "The  Origin  of  Disease"  is  complete,  but,  whether  one 
agrees  with  my  conclusions  or  not,  there  cannot  be  much  doubt  that 
my  observations  of  nature  are  accurate.  The  addition  of  an  elabo- 
rate discussion  on  the  anatomy  and  pathology  of  the  blood-vessels 
would  have  added  nothing  to  its  completeness  and  would  at  the  same 
time  have  buried  the  added  information.  For  these  reasons  I  was 
convinced  that  it  would  be  inexpedient  to  issue  a  new  edition,  that  I 
was  prepared  to  write  upon  the  subject  of  the  human  blood-vessels, 
and  that  the  discussion  of  them  must  not  be  confined  to  their  pathol- 
ogy but  must  include  also  a  consideration  of  their  anatomy.  This 
work  is  the  outcome  of  the  conclusion;  and  it  is  to  be  looked  upon 
as  a  supplement  to  my  book  on  "The  Origin  of  Disease." 

Almost  all  of  the  blood-vessels  from  which  my  illustrations  were 
made,  and  upon  the  appearances  and  conditions  of  which  my  work 


vi  PREFACE 

is  based,  were  obtained  in  the  course  of  my  service  as  physician  to  the 
Pennsylvania  Hospital.  During  the  time  that  I  was  collecting  this 
material  the  hospital  organization  was  such  that  I  myself  made  most 
of  the  autopsies  or  was  present  when  they  were  made.  Every  phy- 
sician to  the  hospital  was  his  own  pathologist,  for  there  was  then  no 
organized  department  of  pathology.  Although  there  cannot  be  any 
doubt  that  the  modern  method  of  the  division  of  labor  is  a  great 
advance,  it  is  certainly  true  that  when  one  man  was  able  personally 
to  make  the  diagnosis  and  direct  the  treatment,  and  afterwards,  it  the 
patient  died,  to  make  the  autopsy  and  examine  with  the  microscope 
portions  of  the  tissues,  the  opportunity  was  afforded  to  learn  some 
things  that  are  likely  to  be  overlooked  when  the  work  is  subdivided. 
The  illustrations  are  original ;  the  camera  lucida  was  used  in  mak- 
ing all  of  them,  and  the  steel  etchings  were  drawn  directly  upon  the 
metal  without  the  use  of  an  intermediate  sketch.  The  artists  exer- 
cised their  best  skill  and  have  succeeded  in  producing  faithful  repre- 
sentations of  nature.  I  learned  in  the  course  of  my  work  not  to 
give  them  much  advice  or  detailed  directions.  Many  of  the  illustra- 
tions in  medical  books  are  no  more  than  diagrams,  and  this  I  think  is 
because  the  artists  are  too  much  restricted  in  drawing  objects  that  they 
themselves  sometimes  feel  they  do  not  understand.  As  they  are  not 
given  sufficient  scope,  they  fail  to  reproduce  that  which  they  see,  as 
they  must  all  try  to  do  in  portrait  or  landscape  work.  Mr.  Hermann 
Faber  made  the  etchings  and  the  pictures  in  color,  and  the  black  and 
white  illustrations  reproduced  by  photographic  process  are  by  Mr. 
Erwin  F.  Faber. 

December  i,  1906. 


CONTENTS 


PAGE 

INTRODUCTION i 

CHAPTER    I 
ARTERIES  AND  VEINS 5 

CHAPTER    II 
CAPILLARIES 16 

CHAPTER   III 
NEW  BLOOD-VESSELS 23 

CHAPTER  IV 
DISEASE  OF  BLOOD-VESSELS  IN  GENERAL 37 

CHAPTER   V 
DISEASE  OF  VEINS 50 

CHAPTER  VI 

DISEASE  OF  THE  RADIAL  ARTERIES  AND  VEINS 61 

(  , 

CHAPTER   VII 
THE  BLOOD-VESSELS  IN  INFLAMMATION,  IN  TUBERCULOSIS,   AND  IN   SYPHILIS   ...      09 

CHAPTER   VIII 
THE  BLOOD-VESSELS  OF  THE  HEART 77 

CHAPTER   IX 
THE  BLOOD-VESSELS  OF  THE  LUNGS 90 

CHAPTER  X 
THE  BLOOD-VESSELS  OF  THE  LIVER 107 

CHAPTER   XI 
THE  BLOOD-VESSELS  OF  THE  SPLEEN 113 

CHAPTER   XII 
THE  B  LOO  i;- VESSELS  OF  THE   KIDNEY 120 

CHAPTER   XIII 

THE  BLOOD- VtssELS  OF  THE  BRAIN  AND  SPINAL  CORD 124 

vii 


LIST  OF  ILLUSTRATIONS 


FIG.  PAGE 

1.  AORTA;  SHRUNKEN  AND    UNSHRUNKEN 10 

2.  VENA  CAVA;  SHRUNKEN  AND  UNSHRUNKEN 10 

3.  FEMORAL  ARTERY;  UNSHRUNKEN 10 

4.  FEMORAL  ARTERY;  SHRUNKEN..'. 10 

5.  FEMORAL  VEIN;  UNSHRUNKEN 10 

6.  FEMORAL  VEIN;  SHRUNKEN 10 

7.  POPLITEAL  ARTERY  AND  VEIN;  UNSHRUNKEN 12 

8.  POPLITEAL  ARTERY  AND  VEIN;  SHRUNKEN 12 

9.  CORONARY  ARTERY;  UNSHRUNKEN 12 

10.  CORONARY  ARTERY;  SHRUNKEN 12 

11.  CORONARY  ARTERY;  UNSHRUNKEN 12 

12.  CORONARY  ARTERY;  SHRUNKEN 12 

13.  NORMAL  RADIAL  ARTERY  AND  VEIN 14 

14.  NORMAL  RADIAL  ARTERY 14 

1 5.  NORMAL  RADIAL  VEIN 14 

16.  VENA  CAVA 14 

17.  SINUS  VENOSUS  OF  THE  HEART 14 

18.  NORMAL  BLOOD-VESSELS  OF  THE  SPINAL  CORD 14 

19.  NEW  ARTERIOLE 28 

20.  THICKENED  BLOOD-VESSEL  OF  THE  SPINAL  CORD,  WITH  NUMEROUS 

CAPILLARIES  IN  ITS  WALL 28 

21.  NEW  BLOOD-VESSELS  IN  LUNG  AND  IN  PLEURA 30 

22.  NEW  BLOOD-VESSELS  IN  THICKENED  PLEURA  AND  IN  LUNG 30 

23.  NEW  BLOOD-VESSELS  OF  THE  LUNG 32 

24.  NEW  BLOOD-VESSELS  IN  NEW  TISSUE 32 

25.  GIANT-CELLS 36 

26.  ANEURISM 42 

27.  ANEURISM 42 

28.  CALCAREOUS  DEPOSIT  IN  THE  RADIAL  ARTERY 44 

29.  ORGANIZED  CLOT    ATTACHED  TO  THE  INTIMA  OF  AN  ARTERY 46 

30.  DISEASED  RADIAL  ARTERY  AND  VEINS 50 

31.  FIBROID  DEGENERATION  OF  A  VEIN 50 

32.  ENDOPHLEBITIS 52 

33.  DISEASED  ARTERY  AND  VEIN  OF  THE  KIDNEY 52 

ix 


x  LIST   OF    ILLUSTRATIONS 

FIG.  PAGE 

34.  DISEASED  VEIN 54 

35.  DISEASED  VEIN 54 

36.  FIBROID  VEIN 58 

37.  FIBROID  VEIN 58 

38.  DISEASED  VEIN  WITH  CAPILLARY  BRANCH 58 

39.  THICKENED  ARTERY  AND  DISEASED  VEIN  OF  THE  MESENTERY 60 

40.  ARTERY  AND  DISEASED  VEIN  FROM  STOMACH 60 

41.  ARTERY  AND  DISEASED  VEIN  OF  THE  COLON 60 

42.  BLOOD-VESSEL  OF  ATYPICAL  UNUSUAL  STRUCTURE 60 

43.  DISEASED  RADIAL  ARTERY  AND  VEINS 62 

44.  NEARLY  NORMAL  RADIAL  ARTERY  AND  VEIN 62 

45.  THICKENED  RADIAL  ARTERY  AND  DISEASED  VEINS 64 

46.  THICKENED  RADIAL  ARTERY  AND  DISEASED  VEINS 64 

47.  DISEASED  RADIAL  ARTERY  AND  VEINS 64 

48.  THICK-WALLED  RADIAL  ARTERY 66 

49.  DISEASED  RADIAL  VEIN 66 

50.  DISEASED  RADIAL  VEIN 68 

51.  DISEASED  AND  NEW  BLOOD-VESSELS  IN  THE  WALL  OF  THE  AORTA.  ...  70 

52.  DISEASED  ARTERIOLE  AND  VENULE  OF  THE  ILEUM 70 

53.  ARTERY  AND  VEINS  IN  INFLAMED  PIA-ARACHNOID  OF  THE  CORD  ....  72 

54.  BLOOD-VESSELS  OF  TUBERCULAR  MENINGITIS  OF  THE  CORD 72 

55.  TUBERCULAR  INFLAMMATION  OF  ARTERY  OF  CORD 74 

56.  TUBERCULAR  INFLAMMATION  OF  VEIN  OF  CORD 74 

57.  TUBERCULAR  PHLEBITIS  OF  THE  CORD 74 

58.  NEARLY  NORMAL  ARTERY  AND  VEIN  OF  LUMBAR  CORD 74 

59.  TERMINAL  ARTERIOLE  OF  HEART 82 

60.  HEART  CAPILLARIES 82 

61.  HEART  CAPILLARIES 82 

62.  LARGE  RETURN  CAPILLARY  OF  THE  HEART 82 

63.  INJECTED  BLOOD-VESSELS  OF  HEART 84 

64.  INJECTED  CAPILLARIES  WITHIN  THE  MUSCULAR  FIBRES  OF  THE  HEART  84 

65.  INJECTED  CAPILLARIES  WITHIN  THE  MUSCULAR  FIBRES  OF  THE  HEART  84 

66.  NORMAL  LARGE  CAPILLARY  OF  HEART 86 

67.  NORMAL  CAPILLARY  NET  OF  HEART 86 

68.  THICKENED  ARTERY  AND  DISEASED  VEINS  OF  THE  HEART 86 

69.  ARTERY  OF  THE  HEART;  NEARLY  NORMAL 86 

70.  DISEASED  ARTERY  OF  THE  HEART 86 

71.  NORMAL  BLOOD-VESSEL  FROM  HEART 86 

72.  DISEASED  BLOOD-VESSEL  OF  THE  HEART 86 

73.  DISEASED  VEIN  OF  HEART 88 


LIST   OF    ILLUSTRATIONS  xi 

FIG.  PAGE 

74.  VEIN  OF  THE  HEART 88 

75.  ARTERY  AND  DISEASED  VEIN  OP  THE  HEART 88 

76.  BRONCHIOLE  OF  INJECTED  LUNG 90 

77.  INFILTRATION  OF  THE  LUNG  WITH  BLOOD 92 

78.  LUNG 94 

79.  LUNG 94 

80.  LUNG 94 

81.  LUNG 98 

82.  LUNG 98 

83.  FIBROID  LUNG 98 

84.  PERIVASCULAR  FIBROSIS  OF  LUNG too 

85.  PERIVASCULAR  AND  PERIBRONCHIAL  PNEUMONIA 100 

86.  FIBROID  VEIN  OF  LUNG 102 

87.  DISEASED  BLOOD-VESSELS  OF  LUNG 102 

88.  CROSS-SECTION  OF  A  PORTAL  VEIN  AND  OF  OTHER  VESSELS  IN  THE 

CAPSULE  OF  GLISSON 108 

89.  THICKENING  OF  A  PORTAL  VEIN  AND  HEPATIC  ARTERY no 

90.  ANTERIOR-INFERIOR    EDGE    OF    A    CIRRHOTIC     LIVER    AND    BLOOD- 

VESSELS      no 

91.  BLOOD-VESSELS  OF  THE  SPLEEN 116 

92.  THREE  BLOOD-VESSELS  IN  A  SPLEEN  TRABECULA 116 

93.  THICKENED  BLOOD-VESSEL  IN  SPLEEN 1 18 

94.  FOUR  THICKENED  BLOOD-VESSELS  OF  THE  SPLEEN 118 

95.  ARTERY  EXTENDING  FROM  PERINEAL  FAT  INTO  KIDNEY 122 

96.  DISEASED  BLOOD-VESSELS  OF  FIBROID  KIDNEY 122 

97.  NORMAL  ARTERY  AND  VENOUS  CAPILLARY  OF  THE  BRAIN 126 

98.  ARTERY  OF  THE  SPINAL  CORD 126 

99.  VEIN  OF  THE  SPINAL  CORD 126 

100.  BLOOD-VESSEL  OF  THE  SPINAL  CORD 126 

101.  DISEASED  ARTERY  FROM  THE  CIRCLE  OF  WILLIS 126 

102.  DISEASED  BASILAR  ARTERY  OCCLUDED  BY  CLOT 128 

103.  INFLAMMATION  OF  A  BLOOD-VESSEL 128 


INTRODUCTION 


IT  has  so  long  been  known  that  the  blood-vessels  are  a  very  im- 
portant part  of  man's  economy  that  it  is  not  necessary  to  apologize 
for  the  publication  of  anything  that  will  add  to  the  sum  of  knowl- 
edge concerning  them.  Human  blood-vessels  have  not  been  exhaus- 
tively studied  and  there  are  no  existing  text-books  which  contain  full 
and  satisfactory  information  in  regard  either  to  their  anatomy  or  to 
their  diseases.  This  book  is  necessarily  incomplete  because  it  is  only 
a  record  of  my  studies.  It  has  been  impossible  to  arrange  my  ma- 
terial as  methodically  as  I  should  like,  because  the  foundation  of  the 
work  is  the  illustrations,  and  these  were  made  from  tissues  that  were  all 
obtained  post  mortem  except  a  few  which  were  removed  by  operation 
from  living  persons.  As  the  vessels,  whether  procured  from  the  dead 
or  from  the  living,  had  to  be  taken  as  they  were  found,  they  are 
grouped  in  the  pictures  according  to  the  positions  they  occupied  in 
the  tissues.  Hence  it  lias  been  found  impracticable  to  produce  a 
systematic  text-book,  for  in  such  works  the  arteries,  veins,  and  capil- 
laries and  their  various  diseases  are  usually  described  in  separate 
chapters,  which  are  arranged  in  the  order  deemed  by  the  author 
best  fitted  to  produce  a  comprehensive  whole  that  can  be  easily  un- 
derstood. My  own  descriptions  have  been  written  in  the  way  the 
pictures  have  indicated  to  be  the  natural  one  according  to  the  group- 
ing of  the  blood-vessels  and  to  the  conditions  of  disease. 

It  is  impossible  to  study  disease  of  the  blood-vessels  without  soon 
learning  that  their  anatomy  is  still  imperfectly  known.  The  correct- 
ness of  this  statement  will  be  readily  accepted  by  any  one  who  has,  for 
instance,  examined  with  the  microscope  the  capillaries  of  the  various 
organs  and  has  tried  to  obtain  an  exact  understanding  of  their  course 
and  appearances  and  who  has  then  read  such  descriptions  of  them  as 
can  be  found.  Within  a  few  years  I  have  myself  pointed  out  the 
fact  that  the  muscular  fibres  of  the  human  heart  are  not  merely  sur- 
rounded by  nets  of  capillaries,  as  was  believed,  but  that  they  are 
penetrated  by  the  capillaries,  and,  besides,  that  the  return  vessels 
accompanying  the  minute  arterioles  of  the  heart  frequently  are  not 


2  HUMAN  BLOOD-VESSELS 

veins  with  three  coats,  but  are  large  capillaries  with  walls  formed  of 
endothelium.1  There  are  so  many  of  these  large  capillaries  in  the 
heart,  their  size  is  so  great,  and  the  shapes  and  appearances  of 
some  of  them  are  so  different  (see  Chapter  VIII.)  from  ordinary  mi- 
nute capillaries  that  it  would  be  more  accurate  if  some  of  the  larger 
ones  were  named  sinuses.  In  the  course  of  this  work  I  shall  demon- 
strate with  pictures  that  the  same  anatomical  peculiarity,  of  arterioles 
having  capillaries  as  their  accompanying  return  vessels,  exists  in  the 
brain  and  in  the  spinal  cord.  Something  of  this  is  known  and  is 
mentioned  in  text-books,2  but  it  has  been  by  no  means  fully  elabo- 
rated and  has  not  yet  become  a  matter  of  common  knowledge. 
The  ordinarily  accepted  descriptions  of  veins  is  that  they  are  like 
arteries  in  their  main  features,  having  three  coats,  intima,  muscularis, 
and  adventitia,  and  that  these  three  coats  are  of  different  thick- 
nesses in  the  two  sorts  of  vessels  rather  than  that  veins  and  arteries 
are  of  essentially  different  structure  and  appearance.  Although  it  is 
certainly  true  that  there  are  points  of  marked  similarity,  I  think  I 
shall  be  able  to  show  that  veins  are  more  radically  different  from 
arteries  than  the  commonly  accepted  descriptions  indicate. 

There  is  still  much  to  be  learned  about  arteries,  but  it  is  beyond 
doubt  true  that  their  appearances  and  characteristics  have  been  more 
fully  and  accurately  described  than  have  those  of  veins  or  capillaries. 
The  differentiation  of  the  walls  of  the  arteries  into  three  separate  coats 
which  can  be  easily  seen  with  the  microscope,  and  which  are  essen- 
tially different  from  one  another,  is  generally  marked,  while  in  veins 
it  is  often  obscure  or  indistinguishable.  Although  the  available 
information  in  regard  to  the  anatomy  ot  the  blood-vessels  is  still  so 
incomplete,  it  would  never  do  to  wait  for  it  to  become  complete 
before  studying  their  diseases.  Anatomy  and  pathology  must  progress 
hand  in  hand,  and  every  addition  made  to  the  one  science  is  sure  to 
help  the  other.  At  the  present  time  it  is  not  possible  for  one  wishing 
to  study  disease  of  blood-vessels  to  obtain  from  books  an  exact  idea 

1  The  Microscopical  Anatomy  of  the  Human  Heart,  by  Arthur  V.  Meigs,  Transactions 
of  the  College  of  Physicians  of  Philadelphia,  April  I,  1891,  and  the  American  Journal  of 
the  Medical  Sciences,  June,  1891.  The  Penetration  of  the  Muscular  Fibres  of  the  Human 
Heart  by  Capillaries,  and  the  Existence  in  that  Organ  of  very  Large  Capillaries,  by  Arthur 
V.  Meigs,  Journal  of  Anatomy  and  Physiology,  vol.  xxxiii. 

3  Normal  Histology,  by  George  A.  Piersol  :  J.  B.  Lippincott  Co.,  Philadelphia,  1900. 


INTRODUCTION  3 

of  their  normal  appearances.  For  instance,  in  order  to  study  disease 
of  the  radial  artery — a  vessel  which  occupies  a  large  share  of  the  at- 
tention of  physicians,  owing  to  the  custom  of  feeling  the  pulse  at  the 
wrist — it  ought  to  be  a  simple  matter  to  turn  to  works  on  anatomy 
and  learn  what  are  the  gross  and  microscopical  appearances  of  this 
vessel.  Text-books  of  anatomy  and  histology,  however,  fail  to  yield 
such  information.  They  are  in  some  respects  most  complete,  and  the 
number  of  facts  that  have  been  accumulated  and  recorded  in  regard  to 
the  blood-vessels  is  enormous  ;  but  the  information  is  general,  and 
when  one  comes  to  consider  particular  vessels,  or  to  study  special 
points,  it  is  necessary  to  return  to  the  direct  observation  of  nature. 
The  obstacles  to  a  satisfactory  study  of  human  blood-vessels  are 
almost  innumerable,  and  the  amount  of  time  that  might  be  expended 
upon  it  is  without  limit. 

In  the  study  of  human  histology  it  is  difficult  to  obtain  healthy 
tissues,  and  in  the  text-books  many  of  the  illustrations  and  descrip- 
tions are  of  the  tissues  of  the  lower  animals.  This  is  unsatisfactory, 
because  it  is  never  possible  to  be  sure  that  such  tissues  are  exactly 
like  the  corresponding  human  tissues. 

Another  obstruction  to  the  increase  of  knowledge  of  the  anatomy 
and  pathology  of  the  blood-vessels  is  that  little  or  no  attention  is  paid 
to  the  fact  that  they  change  as  life  progresses,  so  that  the  blood- 
vessels of  the  old  are  very  different  from  those  of  young  persons. 
Whether  this  change  be  looked  upon  as  a  physiological  one,  as  it 
has  been  considered  by  many  to  be,  or  it  be  conceded  that  there 
is  a  "disease  of  age,"  as  I  myself  think  and  have  tried  to  prove,1 
there  can  be  no  reasonable  doubt  that  the  difference  is  a  real 
one.  It  is  necessary,  therefore,  in  order  to  make  any  further  progress, 
that  it  be  recognized  that  the  blood-vessels  slowly  and  steadily  change 
from  youth  to  age.  At  present  it  is  often  difficult,  and  sometimes  im- 
possible, to  decide  whether  a  particular  vessel  is  diseased  or  if  it  has 
lost  the  characteristics  commonly  attributed  to  vessels  of  its  class  ow- 
ing to  the  changes  due  to  age.  All  intelligent  physicians  are  forced 
to  answer  questions  in  pathology,  and  the  difficulty  that  confronts  the 
practical  physician  when  he  tries  to  answer  the  question  whether  a 
particular  blood-vessel  of  an  elderly  or  old  person  is  diseased,  and  for 

1  The  Origin  of  Disease,  by  Arthur  V.  Meigs,  Chapter  II. :    J.  B.  Lippincott  Co.,  Phila- 
delphia, 1899. 


4  HUMAN  BLOOD-VESSELS 

that  reason  incapable  of  properly  performing  its  function,  or  whether  it 
is  thick  and  stiff  owing  simply  to  the  physiological  changes  of  age,  is 
one  that  presents  itself  almost  every  day  and  is  often  entirely  unanswer- 
able. There  is  no  standard  to  establish  what  is  a  normal  blood-ves- 
sel, and  it  is  actually  the  case  that  for  one  wishing  to  study  disease  of 
such  a  blood-vessel  as  the  radial  artery  it  is  impossible  to  know  where 
to  turn  to  find  an  accurate  description  and  pictures  of  it.  It  is  al- 
most unnecessary  to  say  that  it  would  be  a  great  help  to  the  study  of 
disease  of  blood-vessels  were  it  possible  to  obtain  more  complete  and 
accurate  descriptions  of  their  normal  appearances. 


HUMAN    BLOOD-VESSELS 


CHAPTER    I 
ARTERIES  AND  VEINS 

THE  generally  accepted  descriptions  of  the  histology  of  arteries 
and  veins  are  not  perfectly  exact,  for  they  give  the  impression  that  the 
two  kinds  of  blood-vessels  are  more  nearly  alike  than  is  actually  the 
case.  It  is  true  that  both  arteries  and  veins  have  three  coats  and  are 
composed  of  the  same  kinds  of  tissues  and  that  the  same  sorts  of  cells 
exist  in  both,  but  the  veins  are  more  variable  in  structure.  The  walls 
of  the  veins  are  thinner  and  their  texture  is  looser  than  that  of  arteries. 
They  are  less  satisfactory  objects  to  examine  with  the  microscope  by 
the  methods  of  preparation  in  use  at  the  present  time.  It  is  said 
that  the  external  coat  of  some  veins  contains  muscular  tissue  and  in 
some  veins  muscular  tissue  is  scant  or  is  even  entirely  absent.  In  my 
own  studies  of  human  veins  I  cannot  remember  ever  having  been 
able  to  distinguish  a  fenestrated  elastic  layer,  although  the  fenestrated 
or  plicated  membrane  constitutes  such  a  striking  feature  in  the  great 
majority  of  arteries.  On  the  other  hand,  the  arteries  are  regularly 
formed  of  three  coats,  and  these  coats  are  of  much  more  definite 
structure  than  those  composing  the  walls  of  veins.  A  great  part  of 
the  common  descriptions  of  arteries  and  veins  has  been  gradually  built 
up  from  studies  of  embryology  and  of  the  tissues  of  lower  animals. 
It  will  be  found  that  the  human  tissues  which  become  available  for 
examination  do  not  present  appearances  in  all  respects  in  accord  with 
the  descriptions.  In  my  experience  it  is  exceptional  to  find  the  arte- 
ries and  veins  lined  with  the  fine  layer  of  endothelium  which  according 
to  the  classical  descriptions  always  exists.  Histologists  say  this  is 
owing  to  post-mortem  changes  and  to  the  imperfect  opportunities  for 
the  preservation  of  human  tissues.  This  seems  to  me  a  very  inade- 
quate explanation,  and  I  believe  that  with  the  passing  of  years  the 
blood-vessels  and  particularly  the  arteries  change  much  more  than  has 
been  generally  appreciated.  A  usual  result  is  that  the  intima  is  a 
tissue  of  irregular  thickness  at  different  parts  of  its  circumference. 

5 


6  HUMAN  BLOOD-VESSELS 

This  condition  of  the  intima  of  arteries,  which,  when  fully  developed, 
constitutes  the  disease  endarteritis,  is  so  universal  that  it  is  impossible 
to  look  upon  it  as  being  always  a  disease.  In  its  lesser  forms  of  devel- 
opment it  is  quite  harmless,  and  should  be  set  down  as  a  departure 
from  the  standard  of  normal  which  invariably  comes  with  the  passage 
of  time,  and  it  must  not  be  called  a  part  of  the  "  disease  of  age," 
which  in  its  more  fully  developed  states  is  a  positive  disease  and  is 
easy  to  recognize.  This  irregular  but  almost  universal  thickening  of 
the  intima  of  medium-sized  human  arteries  is  accompanied  by  an 
absence  of  the  lining  layer  of  endothelium.  In  some  arteries  l  the 
endothelial  lining  can  be  distinguished  at  parts  of  the  circumference  of 
the  vessel  and  at  others  the  intima  may  be  seen  to  be  thickened.  The 
tissues  of  the  lower  animals  have  been  too  much  used  for  making  the 
illustrations  of  the  standards  of  histology,  and  an  ideal  has  been  set  up 
which  is  too  rigid.  Sufficient  allowance  has  not  been  made  for  natural 
variations.  The  illustrations  in  text-books  are  generally  too  diagram- 
matic. The  custom  of  describing  arteries  and  veins  as  consisting 
of  three  coats  is  so  firmly  fixed  that  it  would  be  difficult  to  change  it, 
and  it  is  doubtful  if  anything  would  be  gained  were  it  changed,  although 
it  would  probably  be  more  true  to  nature  to  say  they  have  only  two 
coats.  It  is  impossible  to  make  any  distinction  between  perivascular 
connective  tissue  and  the  adventitia  of  arteries  and  veins.  The  thick- 
ness of  the  external  coat  depends  upon  how  much  tissue  was  dragged 
out  with  the  blood-vessel  if  it  has  been  pulled  out  of  the  surrounding 
tissue  and  is  examined  separately,  or  it  depends  upon  the  opinion  of  the 
anatomist  if  a  section  of  a  vessel  is  examined  which  is  still  surrounded 
by  tissue.  The  muscularis  and  the  intima  are  the  only  tissues  of 
arteries  and  veins  which  are  heterogeneous  to  the  organs  or  tissues  in 
which  the  blood-vessels  lie.  The  adventitia  is  fibrous  tissue  and  is  like 
much  of  the  connective  tissue  of  the  body.  It  would  therefore  prob- 
ably be  more  logical  and  more  nearly  scientifically  correct  were  two 
coats  only  attributed  to  the  arteries  and  veins  and  the  adventitia  classed 
as  a  part  of  the  perivascular  connective  tissue. 

The  living  blood-vessels  are  very  different  from  dead  ones,  which 
are  almost  our  only  material  for  study.  In  studying  blood-vessels 
this  fact  should  never  be  forgotten,  and  it  is  just  as  true  of  their  anat- 

1  Origin  of  Disease,  by  Arthur  V.  Meigs,  page  43,  Fig.  8  :  J.  B.  Lippincott  Co.,  Phila- 
delphia, 1899. 


ARTERIES  AND  VEINS  7 

omy  as  it  is  of  their  pathology.  One  of  the  mysteries  of  life  and  death 
is  the  disappearance  at  death  of  the  liquid  blood  that  distends  the  vas- 
cular channels  during  life.  The  relaxed  and  flaccid  or  empty  blood- 
vessels found  in  the  dead  are  very  different  from  the  elastic  and  pulsat- 
ing tubes  that  are  seen  by  surgeons  during  operations  and  by  experi- 
menters upon  living  animals.  Most  of  the  investigations  both  in 
anatomy  and  pathology  are  made  with  dead  tissues,  and  in  studying 
blood-vessels  allowance  must  always  be  made  for  the  changes  that  take 
place  at  the  time  of  death  and  afterwards.  I  say  at  the  time  of  death 
and  afterwards  advisedly,  for,  although  it  is  almost  universally  known 
that  the  dead  tissues  are  different  from  the  living  ones,  it  is  not  so  well 
known,  or  at  any  rate  it  has  not  been  so  much  emphasized  and  made 
a  matter  of  common  knowledge,  that  the  dead  tissues  which  are  studied 
have  undergone  a  further  great  change  in  the  course  of  their  prepara- 
tion for  investigation. 

It  is  to  microscopical  study  that  I  now  especially  refer.  Tissues 
which  are  to  be  examined  with  the  microscope  are  generally  sub- 
jected to  processes  which  are  more  or  less  elaborate.  Some  of 
the  lower  animals  have  transparent  tissues,  and  these  when  suffi- 
ciently thin  can  be  examined  with  the  microscope  while  still  living, 
and  in  this  way  has  been  obtained  some  of  the  most  valuable  informa- 
tion in  regard  to  anatomy  and  physiology.  Teased  bits  of  the  tissues 
of  recently  killed  animals  and  of  criminals  that  have  been  executed 
have  been  used  for  study,  and  such  tissue  probably  has  undergone  a 
minimum  of  change  after  death.  Frozen  sections  obtained  under 
proper  precautions  are  also  of  use  and  have  done  their  part  in  ad- 
vancing the  sciences  of  anatomy  and  pathology.  All  the  more  elabo- 
rate methods,  however,  used  in  making  permanent  preparations  for 
microscopical  examination  involve  the  immersion  of  the  tissues  in  vari- 
ous reagents,  and  no  one  of  these  methods  is  free  from  the  objection 
that  the  tissue  is  very  much  shrunk.  This  shrinkage  must  necessarily 
change  the  general  appearance  of  the  tissue  as  well  as  the  shapes  and 
appearance  of  the  cells  and  the  other  elements  of  which  tissues  are 
composed. 

After  trying  for  a  good  while  to  discover  a  method  to  eliminate 
this  source  of  error,  it  struck  me  that  in  dealing  with  blood-vessels 
something  might  be  accomplished  in  that  direction  by  placing  a 
rod  of  some  rigid  material,  like  glass,  within  the  calibre  of  a  vessel  to 


8  HUMAN  BLOOD-VESSELS 

be  examined  with  the  microscope.  This  experiment  I  have  tried.1 
Rods  of  glass  were  placed  as  soon  as  possible  after  death  in  blood- 
vessels to  be  examined,  and  then  the  tissue  together  with  the  glass  was 
put  in  whatever  reagents  were  needed.  The  glass  prevents  any  re- 
duction in  size  of  the  calibre  of  the  vessel.  This  does  not  prevent  the 
shrinkage  that  takes  place  in  arteries  and  veins  at  the  time  of  death 
when  their  fluid  contents  leave  them,  but  it  entirely  prevents  the  fur- 
ther reduction  of  their  lumina  which  ordinarily  occurs  in  preparation 
for  section  for  microscopical  examination. 

The  sections  I  have  had  made  were  subjected  to  the  paraffin- 
embedding  process.  The  glass  rods  used  were  as  large  as  could  be 
got  into  the  vessels  without  stretching  them,  and  the  glass  was  left 
in  them  while  they  were  in  the  various  reagents  and  while  they 
were  soaking  in  the  warm  melted  paraffin  with  which  the  tissue 
must  be  permeated.  The  permeation  with  paraffin  is  the  last 
stage  of  the  process,  and  the  glass  was  not  taken  out  of  the  vessels 
until  they  were  removed  from  the  oven  ready  for  the  paraffin  to  be 
cooled  and  sections  cut.  There  was  no  opportunity,  therefore,  any- 
where in  the  course  of  the  process  for  the  calibre  to  shrink.  When 
preparing  sections  in  this  way  I  have  always  kept  a  second  piece  of  the 
artery  01  vein  that  was  being  studied,  and  have  carried  it  through  the 
same  process  of  preparation  and  at  the  same  time.  Thus  there  was 
always  a  section  of  a  vessel  which  had  had  a  glass  rod  in  it  to  prevent 
shrinkage,  and  another  section  which  had  been  left  free  to  shrink  as  it 
might  and  to  assume  whatever  irregular  shape  the  shrinkage  tended 
to  give  it. 

The  examination  of  sections  thus  prepared  gives  ocular  demonstra- 
tion of  a  number  of  things  that  were  already  known  by  inference 
but  which  lacked  direct  proof.  A  section  of  any  vessel  which  has 
had  glass  in  it  while  in  course  of  preparation  for  cutting  always 
remains  of  the  same  shape  as  the  glass  body,  and  I  have  generally 
used  circular  rods  of  hollow  cylinders,  but  other  sections  of  the  same 
vessel  prepared  without  anything  in  its  calibre  are  often  irregular  in 
outline.  This  irregularity  is  very  variable  and  is  due  to  a  number  of 

'Transactions  of  the  Pathological  Society  of  Philadelphia,  1901.  A  Demonstration  of  the 
Shrinking  of  Blood-vessels  that  occurs  as  they  are  ordinarily  prepared  for  Microscopic  Exam- 
ination, and  of  the  Distortion  of  the  Tissues  which  is  caused  by  this  Shrinkage  :  Also  the 
Exhibition  of  New  Blood-vessels  in  the  Inner  Layers  of  Diseased  Veins.  By  Arthur  V.  Meigs. 


ARTERIES  AND  VEINS  9 

causes.  Large  vessels  generally,  and  veins  in  particular  because  their 
walls  are  thin,  almost  always  collapse  and  assume  irregular  outlines  ; 
they  seldom  preserve  their  natural  circular  shape.  The  smaller  ves- 
sels, and  especially  those  with  walls  that  have  been  thickened  by 
disease,  usually  retain  their  natural  circular  form. 

The  irregularity  of  shape  of  blood-vessels  cut  for  examination  with 
the  microscope,  however,  is  not  due  alone  to  their  collapsing  because 
their  walls  were  not  thick  enough  to  retain  their  form,  but  also 
to  the  shrinking  of  the  tissue  in  accordance  with  variations  of  the 
thickness  of  the  vessel-walls  at  different  parts.  This  variation  of  thick- 
ness at  different  places  occurs  even  in  healthy  vessels  and  to  a  still 
greater  extent  as  a  result  of  disease.  It  is  also  true  that  different 
kinds  of  tissue  shrink  very  differently  when  they  are  soaked  in  the 
various  reagents  used  in  preparing  sections.  The  adventitia  of  the 
aorta,  for  instance,  which  is  of  loose  and  open  structure,  will  shrink 
more  than  the  intima,  which  is  denser.  This  is  easily  demonstrated 
by  preparing  a  small  square  section  of  the  whole  thickness  of  the 
human  aorta.  Soon  after  it  is  placed  in  the  preservative  fluid  it  bends 
itself  backwards,  the  intima  forming  the  outer  and  longer  curve,  while 
the  adventitia  forms  the  shorter  arc.  Sections  of  blood-vessels  are 
often  wavy,  more  or  less  irregular  circles,  or  the  vessels  may  collapse 
in  such  a  way  that  the  sections  are  without  any  regularity  of  form.  In 
text-books  of  histology  blood-vessels  are  generally  described  as  cylin- 
drical, but  in  truth  it  is  the  exception  when  sections  of  them  are  cir- 
cular. If  they  have  not  collapsed  owing  to  their  walls  being  too  thin 
to  retain  their  cylindrical  shape,  the  changes  that  occur  with  the  ad- 
vance of  years  cause  the  walls  to  be  of  uneven  thickness,  and  then 
irregular  shrinkage  in  course  of  preparation  for  section  inevitably 
destroys  the  circular  form.  Disease,  if  it  be  present,  may  produce  an 
infinite  variety  of  unexpected  appearances. 

The  plicated  membrane,  or  fenestrated  membrane  of  Henle,  as  it 
is  also  called,  is  an  important  anatomical  landmark  in  arteries,  and 
it  is  reputed  to  be  often  the  seat  of  origin  of  disease.  In  the 
microscopical  study  of  arteries  this  membrane  is  a  striking  feature, 
constituting  as  it  does  the  line  of  separation  of  the  intima  from  the 
muscularis.  It  is  named  the  plicated  membrane  because  it  ordinarily 
appears  as  a  wavy  or  folded  line  when  seen  in  sections  of  arteries. 
Histologists  know,  of  course,  that  the  folding  is  due  to  post-mortem 


io  HUMAN  BLOOD-VESSELS 

shrinking  and  that  during  life  the  membrane  is  a  cylindrical  layer  of 
elastic  tissue.  Two  sections  prepared  as  I  have  described,  one  with 
glass  in  its  calibre  and  the  other  without,  show  very  clearly  this  pecu- 
liarity of  the  plicated  membrane.  The  sections  which  have  had  no 
glass  in  their  lumina  are  generally  irregular  in  outline  instead  of  being 
perfectly  circular,  and  are  much  smaller. 

Figs,  i,  2,  3,  4,  5,  6,  7,  and  8,  which  show  blood-vessels  that  were 
treated  by  the  method  described,  demonstrate  in  the  most  satisfactory 
manner  both  the  irregularity  of  outline  of  the  vessels  that  were  allowed 
unimpeded  to  shrink,  and  that  this  shrinkage  is  usually  such  as  to 
cause  a  very  great  reduction  in  the  size  of  the  calibre.  Fig.  I  shows  the 
aorta.  One  of  the  sections  was  allowed  to  shrink  and  the  other  was 
prepared  with  glass  cylinders  in  its  calibre.  The  shrunken  section  is 
of  an  irregular  oval  shape  and  its  wall  is  about  twice  as  thick  as  that 
of  the  other  section.  The  odd  shape  of  the  unshrunk  section  is  due 
to  the  fact  that,  as  I  had  no  glass  cylinder  of  such  a  size  as  exactly  to 
fit  the  opening,  it  became  necessary  to  place  one  large  glass  tube  and 
other  smaller  ones  inside  the  artery  to  fill  it.  Fig.  2  represents  the 
vena  cava.  The  opening  of  the  unshrunk  section  must  be  three  or 
even  four  times  as  large  as  that  of  the  shrunk  one,  and  its  wall  is  much 
thinner  but  of  extremely  irregular  thickness.  On  the  right-hand  side 
of  the  picture  the  wall  is  fully  three  times  thicker  than  it  is  on  the  left. 
The  irregularly  twisted  and  folded  shape  of  the  shrunk  section  is  due 
to  the  effect  of  the  preservative  fluids  upon  the  vein,  which  is  of  looser 
texture  and  softer  than  arterial  tissue.  It  is  very  different  from  that 
of  the  aorta  (Fig.  i).  Figs.  3  and  4  show  shrunk  and  unshrunk  sec- 
tions of  the  femoral  artery.  The  great  difference  of  the  size  of  the 
openings,  and  the  fact  that  the  wall  is  very  much  thicker  in  the  section 
in  which  the  shrinkage  was  allowed  to  go  on  unimpeded,  are  graphically 
shown.  Although  the  sections  are  enlarged  only  eight  times,  the  three 
coats  of  which  the  vessel-walls  are  formed  can  be  easily  distinguished, 
and  they  are  even  more  distinct  in  the  shrunk  than  in  the  unshrunk 
section. 

Figs.  5  and  6  illustrate  the  femoral  vein  shrunk  and  unshrunk.    Their 
appearances  are  so  different  that  it  is  difficult  to  believe  that  they  are 
pictures  of  the  same  vessel.     The  wall  of  the  shrunk  section  is  very 
much  thicker    than    that    of  the   unshrunk    one   and   it   is    folded 
Although  the  enlargement  is  the  same  as  that  of  the  femoral  artery 


FIG.  i. — AORTA;  SHRUNKEN  AND  UNSHRUNKEN.     (ACTUAL  SIZE.) 

From  a  man  of  thirty-three  years  who  died  of  pulmonary  congestion.  The  section  to 
the  left  had  glass  tubes  placed  in  its  lumen  at  the  time  the  post-mortem  was  made  ;  both  it 
and  the  section  represented  by  the  picture  to  the  right  were  then  preserved  in  alcohol.  The 
amount  of  shrinkage  is  easily  seen,  and  it  is  also  evident  that  the  wall  of  the  shrunken  vessel 
is  thicker  than  that  of  the  unshrunken  one.  A  number  of  the  following  figures  are  from  the 
same  case. 


FIG.  2. — VENA  CAVA;   SHRUNKEN  AND  UNSHRUNKEN.     (ACTUAL  SIZE.) 

From  the  same  case  as  Fig.  i.  To  the  right  the  shrunken,  to  the  left  the  unshrunken 
section.  The  lumen  of  the  shrunken  section  is  much  smaller  than  that  of  the  other  one  and 
its  wall  is  thickened  and  is  folded.  The  wall  of  the  unshrunken  section  is  of  very  varying 
thickness  at  different  parts.  It  might  have  been  anticipated  that  the  loose  texture  and  thin 
wall  of  a  vein  would  shrink  and  become  distorted  more  than  the  firmer  and  stiffer  artery. 
/,  a  region  represented  more  highly  magnified  by  Fig.  16. 


FIG.    i. 


FIG.  3. — FEMORAL  ARTERY  ;  UNSHRUNKEN.  (X  8. ) 

From  the  same  case  as  Fig.  i.     Shrinkage  was  prevented  by  a  glass  rod.     The  contrast 
with  Fig.  4  is  striking,  for  the  lumen  is  very  much  larger  and  the  wall  much  thinner. 

FIG.  4. — FEMORAL  ARTERY;  SHRUNKEN.     (X  8.) 

•From  the  same  case  as  Fig.  I.  The  usual  shrinkage  was  allowed  to  occur.  The  contrast 
is  great,  for  the  calibre  is  small  and  the  vessel  wall  thick  and  somewhat  corrugated  upon  the 
edges  from  the  drawing  together  of  the  tissue. 


FIG.  3. 


FIG.  4. 


FIG.  5.— FEMORAL  VEIN;  UNSHRUNKEN.     (X  8. ) 

From  the  same  case  as  Fig.  I .  The  lumen  of  the  vein .  is  large  and  it  is  circular.  The 
wall  is  of  very  varying  thickness  at  different  parts  of  the  circle.  The  outer  part  of  the  wall 
below  and  to  the  left  contains  many  bundles  of  tissue  which  run  in  the  direction  of  the 
length  of  the  vein.  When  examined  with  higher  power  these  appear  to  be  involuntary 
muscle.  No  such  muscular  layer  is  represented  in  the  pictures  showing  the  ordinary  his- 
tological  condition  of  veins.  The  portion  of  vein  shown  was  prepared  with  a  glass  tube  in  it. 


FIG.  5. 


FIG.  6. — FEMORAL  VEIN;  SHRUNKEN.     (X  8. ) 

From  the  same  case  as  Fig.  I.  The  lumen  of  the  vein  is  very  small  in  comparison  with 
Fig.  5  and  is  °f  irregular  shape.  The  wall  is  thicker  from  shrinkage  and  is  folded.  It  is 
even  less  like  the  ordinary  histological  standards,  for  the  longitudinal  bands  of  muscle  are 
more  strikingly  shown. 


FIG.  6. 


ARTERIES  AND  VEINS  n 

(eight  diameters),  there  is  no  such  distinctly  recognizable  differentiation 
into  intima,  muscularis,  and  adventitia  as  in  the  case  of  the  artery. 
The  wall  of  the  unshrunk  section  is  very  irregular  in  thickness,  while 
in  the  shrunk  section  this  difference  is  to  a  great  extent  lost,  perhaps 
owing  to  the  folding  and  irregularity  of  shape.  When  the  sections 
from  which  these  two  drawings  were  made  are  examined  under  greater 
amplification,  it  is  seen  that  the  vasa  vasorum  are  not  confined  to  the 
outer  fibrous  layer,  as  it  is  usually  set  down  in  the  text-books  that  the 
vasa  vasorum  are  confined,  but  that  they  extend  into  the  deeper  layers 
of  the  vein  adjacent  to  the  lumen. 

In  Figs.  7  and  8  are  seen  illustrations  of  the  popliteal  artery 
and  vein  both  shrunk  and  unshrunk.  They  were  drawn  from  prep- 
arations of  diseased  blood-vessels,  but,  notwithstanding  this,  they 
show  a  number  of  anatomical  points  of  interest.  The  difference 
in  the  size  of  the  openings  and  in  the  thickness  of  the  walls  due  to 
shrinkage  is  great,  and  is  easily  seen.  It  is  notable  that  in  the 
shrunk  section  the  calibre  of  the  vein  is  smaller  than  that  of  the  artery 
and  its  wall  thicker,  while  in  the  unshrunk  section  the  vein  has 
thinner  walls  and  a  very  much  larger  calibre  than  the  artery.  The 
loose  texture  of  the  tissue  of  the  vein  has  caused  it  to  shrink  much 
more  in  the  preservative  fluids  than  the  denser  artery.  The  irregu- 
larity of  thickness  of  these  vessels  is  striking,  and  there  is  no  known 
law  determining  which  portion  of  the  vessel  is  thickest  and  which 
thinnest.  At  one  time  I  thought  that  blood-vessels  which  lie  in 
pairs  are  thickest  at  their  contiguous  parts,  but  these  sections  show 
that  such  is  not  the  case,  for,  while  the  thickest  part  of  the  vein  is  that 
which  abuts  against  the  artery,  the  opposite  obtains  in  the  artery, 
the  thickest  part  of  its  wall  being  that  which  is  furthest  away  from  the 
vein.  When  this  popliteal  vein  is  examined  with  greater  amplification, 
it  becomes  evident  that  it  possesses  many  characteristics  commonly 
attributed  to  arteries  :  to  so  great  an  extent  is  this  the  case  that 
were  it  not  that  the  two  vessels  were  removed  together  and  that  it  is 
therefore  impossible  that  a  mistake  could  be  made,  the  vein  might 
readily  be  taken  to  be  an  artery. 

As  a  result  of  disease  blood-vessels  frequently  become  so  much 
altered  in  appearance  that  they  lose  their  natural  characteristics,  and 
arteries  and  veins  become  indistinguishable.  Figs.  9  and  10  show  the 
coronary  artery  of  the  heart  unshrunk  and  shrunk.  Fig.  1 1  is  a  por- 


12  HUMAN  BLOOD-VESSELS 

tion  of  the  vessel  wall  from  Fig.  9  more  highly  magnified,  and  Fig. 
12  is  a  portion  from  Fig.  10  more  highly  magnified.  These  four 
pictures  demonstrate  that  several  of  the  appearances  that  are  com- 
monly seen  in  sections  of  blood-vessels  prepared  for  microscopical 
examination  in  the  ordinary  way  are  due  to  shrinkage  and  are  there- 
fore unnatural.  In  Fig.  12  the  plicated  membrane  is  folded,  as  it 
always  is  when  the  shrinking  is  allowed  to  go  on  unimpeded,  but  in 
Fig.  1 1 ,  which  was  prepared  with  glass  in  the  calibre  of  the  vessel,  the 
plicated  membrane  appears  as  a  straight  line.  It  is  of  course  well 
known  that  the  folds  are  due  to  post-mortem  changes,  but  the  method 
I  have  devised  for  preventing  the  shrinking  after  death  makes  an 
ocular  demonstration  of  what  was  previously  known  only  by  deduc- 
tion. Blood-vessels  containing  ante-mortem  clots  sometimes  show 
the  plicated  membrane  straight  (see  Fig.  102)  in  the  same  way  as  the 
sections  prepared  with  glass  rods  in  their  calibres. 

In  studying  the  muscularis  of  sections  of  arteries  prepared  in  the 
two  ways,  unshrunk  and  shrunk,  another  curious  and  interesting 
feature  appears,  which  is  shown  by  Figs.  11  and  12.  When  the 
muscular  coat  of  an  artery  that  has  been  prepared  for  section  in  the 
ordinary  way,  so  that  its  calibre  has  been  greatly  reduced  owing  to  the 
shrinking  caused  by  the  various  reagents,  is  examined  under  a  mod- 
erately high  power  of  the  microscope,  the  muscle  appears  as  if  it  were 
composed  of  a  material  formed  of  meshes — it  resembles  basket-ware. 
If  the  shrinkage  has  been  impeded,  the  muscular  coat  looks  very  dif- 
ferent ;  there  is  little  or  no  resemblance  to  basket-ware,  for  the  muscle 
appears  to  be  composed  of  concentric  lines.  In  sections  prepared 
with  a  glass  rod  in  the  artery  (Fig.  11)  the  muscle  nuclei  are  nearly 
straight  and  all  run  in  the  same  direction,  forming  parallel  lines;  on 
the  other  hand,  in  sections  in  which  the  shrinkage  was  allowed  to 
occur  unimpeded  (Fig.  12)  the  nuclei  are  irregularly  placed,  most  of 
them  lying  with  their  long  diameter  more  or  less  across  the  line  of 
the  general  circuit  of  the  artery.  Besides  this  the  nuclei,  instead  of 
being  straight,  are  of  very  irregular  shapes.  Most  of  them  are  bent 
and  some  are  twisted  and  turned  almost  into  the  shapes  of  irregular 
spirals.  A  comparison  of  Figs.  1 1  and  1 2 — which  are  sections  through 
the  entire  thickness  of  the  wall  of  the  same  artery,  one  prepared  with  a 
glass  rod  in  its  calibre  and  the  other  allowed  to  shrink  unimpeded — 
shows  how  much  thicker  the  three  coats  are  when  shrunk  and  how 


FIG.  7. — POPLITEAL  ARTERY  AND  VEIN;  UNSHRUNKEN.     (X  8.) 

From  a  youth  of  eighteen  years  whose  leg  was  amputated  above  the  knee  for  osteo- 
sarcoma  of  the  thigh.  The  popliteal  artery  (a)  and  vein  (z/)  and  a  small  blood-vessel  (A). 
Glass  rods  were  inserted  in  the  artery  and  vein  to  prevent  shrinkage.  All  three  of  the  ves- 
sels are  a  good  deal  thicker-walled  than  is  natural,  and  the  tissue  composing  h  is  diseased  so 
that  it  is  impossible  to  distinguish  whether  it  is  an  artery  or  a  vein.  The  calibres  of  a  and 
•v  are  circular  because  they  were  held  in  that  form  by  the  glass  rods.  The  walls  are  strik- 
ingly and  very  irregularly  thickened,  and  it  is  noticeable  that  the  thinnest  part  of  the  artery 
wall  is  where  it  abuts  against  the  vein,  and  its  thickest  part  far  from  the  vein.  Fig.  8  is  a 
section  of  the  same  blood-vessels,  but  prepared  without  glass  rods  and  therefore  shrunken. 

FIG.  8. — POPLITEAL  ARTERY  AND  VEIN;  SHRUNKEN.     (X  8.) 

From  the  same  patient  as  Fig.  7.  The  blood-vessels  were  preserved  in  alcohol  but  with- 
out glass  rods  in  them  and  they  shrunk,  a,  popliteal  artery  ;  v,  popliteal  vein ;  h,  the 
blood-vessel  h  in  Fig.  7-  It  cannot  be  ascertained  whether  h  is  an  artery  or  a  vein,  but  it  is 
more  like  a  vein,  for  its  muscular  tissue  has  the  open-meshed  structure  that  is  common  in 
diseased  veins.  The  walls  of  the  artery  (a)  and  vein  (v)  are  greatly  but  irregularly  thick- 
ened, and  are  also  folded  and  corrugated,  owing  to  the  shrinkage.  It  is  notable  that  the  vein 
here  is  thicker- walled  and  has  a  smaller  calibre  than  the  artery,  although  exactly  the  contrary 
is  the  case  in  the  unshrunken  section  (Fig.  7). 


a    ,.; 


FIG.  8. 


FIG.  9. — CORONARY  ARTERY;  UNSHRUNKEN.     (X  8. ) 

From  the  same  case  as  Fig.  i.  Section  in  which  a  glass  rod  was  inserted  to  prevent 
shrinkage.  Fig.  10  shows  a  portion  of  the  same  artery  in  which  no  rod  was  placed.  The 
difference  in  the  size  of  the  lumen  and  in  the  thickness  of  the  wall  of  the  vessel  is  striking. 
k,  the  region  represented  more  highly  magnified  by  Fig.  1 1 . 

FIG.   10. — CORONARY  ARTERY;  SHRUNKEN.     (X  8.) 

From  the  same  case  as  Fig.  i.  This  portion  of  the  vessel  was  preserved  without  any 
glass  rod  in  it,  and  it  therefore  underwent  the  usual  shrinking.  Contrasted  with  Fig.  9  the 
smaller  size  of  the  lumen  and  the  greater  thickness  of  the  wall  are  striking.  /,  the  region 
represented  more  highly  magnified  by  Fig.  12. 


FIG.  9. 


FIG.   10. 


FIG.   ii. — CORONARY  ARTERY;  UNSHRUNKEN.     (X  240.) 

The  region  k  from  Fig.  9  more  highly  magnified.  It  is  a  section  through  the  entire  wall 
of  the  artery,  which  is  normal  except  for  thickening  of  the  intima.  Such  thickening  is  the 
commonest  disease  of  arteries,  and  it  is  so  common  in  young  as  well  as  in  older  persons  that 
it  may  almost  be  said  to  be  universal,  i,  intima  ;  /,  plicated  membrane  ;  m,  muscularis  ;  a, 
adventitia.  The  contrast  is  striking  between  this,  which  represents  the  portion  of  the  vessel 
in  which  shrinkage  was  prevented  by  the  introduction  of  a  glass  tube,  and  Fig.  12,  which 
represents  a  portion  of  the  vessel  in  which  the  usual  shrinkage  that  takes  place  in  specimens 
preserved  in  alcohol  was  allowed  to  occur.  The  total  thickness  of  the  vessel  wall  is  much 
less  here  because  the  shrinkage  was  prevented  and  each  one  of  the  three  coats  is  less  thick. 
Besides  this,  the  plicated  membrane  is  straight,  none  of  the  usual  folds  being  present.  The 
muscle  nuclei  are  nearly  all  straight,  and  are  placed  in  positions  concentric  with  the  circle 
of  the  artery.  Their  condition  here  is  strikingly  different  from  that  of  the  muscle  seen  in 
Fig.  1 2  and  much  more  like  that  which  exists  during  life. 

FIG.   12. — CORONARY  ARTERY;  SHRUNKEN.     (X  240.) 

The  region  /  from  Fig.  10  more  highly  magnified.  It  is  a  section  through  the  entire  wall 
of  the  artery,  i,  intima ;  /,  plicated  membrane ;  m,  muscularis  ;  a,  adventitia.  The  total 
thickness  of  the  vessel  wall  is  much  greater  than  in  Fig.  1 1 ,  and  each  of  the  three  coats 
is  thicker.  The  plicated  membrane  is  folded  as  usual  and  the  intima  shows  the. result  of  the 
shrinkage.  The  change  in  the  muscle  nuclei  is  striking.  Owing  to  the  shrinkage  they  are 
more  crowded  ;  they  are  twisted  like  corkscrews,  and  are  set  at  varying  angles  across  the' 
circle  formed  by  the  artery,  instead  of  being  placed  concentrically.  It  is  this  irregular  sit- 
uation of  the  elongated  nuclei  that  usually  causes  the  arterial  muscularis  to  resemble  basket- 
work  when  examined  with  the  microscope. 


FIG.  ii. 


FIG.  12. 


v-..**     ;  „       •-.?«•  *     i 
a  .      *«9   e 


"  *s  -- 

-s«:; 


«•->• 

•"^*,"x—      «,_     *Ws». 


ARTERIES  AND  VEINS  13 

different  the  tissues  appear.  In  the  unshrunk  section  (Fig.  ii)the 
plicated  membrane  is  straight  and  the  muscle  nuclei  lie  in  parallel 
lines,  which  entirely  destroys  the  resemblance  to  basket-ware  which 
is  such  a  striking  feature  in  sections  of  the  muscularis  of  arteries  pre- 
pared in  the  ordinary  way  and  examined  with  less  amplification  than 
was  used  for  this  drawing.  This  illustration  much  more  nearly  repre- 
sents the  appearance  of  the  different  tissues  of  the  blood-vessels  during 
life  than  do  the  ordinary  pictures  and  descriptions  in  text-books  of 
histology. 

Double  sets  of  sections  prepared  in  the  way  that  has  been  described, 
one  set  with  glass  in  the  calibres  of  the  blood-vessels  to  prevent 
shrinkage  and  the  other  allowed  to  shrink  unimpeded  in  the  reagents, 
demonstrate,  as  has  been  shown,  various  points  of  interest.  They 
show  the  very  great  shrinkage  which  occurs  in  consequence  of  the 
action  of  the  various  liquid  reagents  in  which  one  after  another  the 
tissues  are  soaked.  The  experiment  proves  that  as  a  general  thing 
veins  shrink  more  than  arteries.  This  is  because  the  veins  are  formed 
of  a  material  which  is  of  looser  texture  than  that  of  which  the  denser 
arteries  are  composed.  The  tissue  of  veins  makes  me  think  of  the 
open-meshed  appearance  of  elastic  webbing,  while  arteries  are  hard 
and  dense  like  India  rubber  bands.  The  sections  demonstrate  that 
the  folding  of  the  plicated  membrane  is  the  result  of  post-mortem 
shrinking  and  that  the  basket-ware  appearance  of  the  muscular  tissue 
of  arteries  is  principally  due  to  the  distortion  of  the  nuclei  and  to  their 
falling  into  unnatural  positions  irregularly  across  the  general  line  of 
the  arterial  circumference. 

Figs-  I3»  !4»  and  15  represent  a  radial  artery  and  vein  which 
were  prepared  in  the  usual  way  by  the  paraffin  method,  no  effort 
having  been  made  to  prevent  shrinkage.  It  is  impossible  to  obtain 
human  blood-vessels  which  can  be  known  with  absolute  certainty  to 
be  normal,  but  these  seem  to  be  fair  types  of  the  normal  condition  at 
twenty-five  years  of  age.  They  show  a  number  of  points  of  interest. 
The  muscularis  of  the  artery  in  Fig.  13  presents  the  basket-ware 
appearance  to  which  allusion  has  been  made  as  being  one  of  the 
common  characteristics  of  such  tissue.  The  intima  is  not  a  thin  and 
even  band  lined  with  endothelium,  as  it  is  described  in  text-books, 
but  a  cellular  tissue  which  is  of  varying  thickness  at  different  parts  of 
the  circumference.  The  nature  of  this  tissue  is  better  shown  by  Fig. 


i4  HUMAN  BLOOD-VESSELS 

14,  which  is  an  illustration  of  a  part  of  the  wall  of  the  artery  more 
highly   magnified. 

One  of  the  most  striking  characteristics  of  the  middle-sized  and 
smaller  arteries  of  man  is  this  irregularity  of  thickness  of  the  intima. 
Embryological  studies  seem  to  prove  conclusively  that  the  arteries  of 
man  as  well  as  those  of  lower  animals  are  formed  according  to  well- 
ordered  laws  and  have  during  the  earlier  periods  of  life  the  appear- 
ances that  are  to  be  found  described  in  text-books.  The  examina- 
tion of  a  great  number  of  arteries  under  circumstances  and  conditions 
as  varied  as  possible  has  convinced  me  that  typically  normal  human 
arteries  are  almost  impossible  to  find.  Pathologists  have  observed 
that  thickening  of  the  lining  of  the  arteries  is  a  very  common  result 
of  disease  and  they  have  named  it  endarteritis.  My  own  studies 
have  forced  me  to  conclude  that  it  is  impossible  to  make  an  abso- 
lute distinction  between  the  slighter  degrees  of  endarteritis  and  the 
little  irregularities  of  thickness  of  the  intima  which  should  not  be 
considered  as  disease  and  which  are  found  in  all  human  arteries,  even 
in  those  of  children  and  of  infants.  The  point  I  wish  to  emphasize  is 
that  all  arteries  removed  from  human  bodies  after  death  will  be  found 
to  have  more  or  less  irregularity  of  thickness  of  the  intima  such  as 
is  shown  by  Fig  13. 

Fig.  1 5  is  a  more  highly  magnified  portion  of  the  wall  of  the  radial 
vein  shown  in  Fig  13.  Although  the  three  layers — intima,  muscularis, 
adventitia — can  without  difficulty  be  distinguished,  the  vein  is  but  little 
like  the  illustrations  and  descriptions  found  in  text-books. 

A  consideration  of  the  information  to  be  obtained  from  text-books 
of  anatomy  and  histology  has  forced  upon  me  the  opinion  that,  while 
the  peculiarities  of  arteries  have  been  only  imperfectly  described,  the 
study  of  veins  has  as  yet  hardly  begun.  Fig.  16  shows  a  section 
through  the  wall  of  the  vena  cava,.  Fig.  2,  more  highly  magnified,  and 
Fig.  17  depicts  a  section  of  the  sinus  venosus  of  the  heart.  These  two 
.veins  are  very  unlike  the  ordinary  descriptions  of  veins.  The  wall 
of  the  vena  cava  is  divided  into  three  layers,  but  the  intima  is  com- 
posed of  loose- meshed  tissue  which  is  unlike  the  descriptions  of  the 
intima  of  veins.  The  middle  layer  is  indeed  formed  of  muscular 
tissue,  but  it  is  odd  looking  and  not  like  common  involuntary  muscle, 
and  is  besides  disposed  in  bundles  which  run  in  the  direction  of  the 
length  of  the  blood-vessel,  there  being  no  circular  muscular  layer 


FIG.  13. — NORMAL  RADIAL  ARTERY  AND  VEIN.      (X  20.) 

From  a  negro  woman  twenty-five  years  old  who  died  of  meningitis.  The  artery  is  to  the 
left,  and  it  is  as  nearly  normal  as  any  of  the  arteries  of  persons  who  have  died  of  disease. 
The  intima  is  always  as  thick  as  it  is  here  represented,  f  is  a  region  represented  more  highly 
magnified  by  Fig.  14.  The  vein  is  the  thin-walled  vessel  to  the  right.  The  variation  of  the 
thickness  of  the  wall  is  probably  due  to  obliquity  of  section,  g  is  a  part  which  is  shown 
more  highly  magnified  by  Fig.  15.  The  vein  appears  to  be  normal. 


FIG.   13. 


FIG.   15. — NORMAL  RADIAL  VEIN.     (X  240.) 

The  region  g  from  Fig.  13  more  highly  magnified,      t,  intima  ;   m,  muscularis  ;  a,  adven- 
titia.     It  is  very  unlike  the  ordinary  descriptions  of  veins  in  the  text-books. 


FIG.   15. 

%.-.  -•*'•.  i-ii^S.. 


« 

I  m 

>    V-- 


FIG.   15. — NORMAL  RADIAL  VEIN.     (X  240. 
The  region  g  from  Fig.  13  more  highly  magnified,      i   inHrv>o  .    - 


FIG.   16. — VENA  CAVA.     (X  50. ) 

From  the  same  case  as  Fig.  I.  The  region  t  from  Fig.  2.  It  is  not  like  any  ordinary 
vein,  but  strongly  resembles  Fig.  17.  x,  the  lining;  y,  the  middle  portion  ;  z,  the  exter- 
nal portion  of  the  vena  cava.  The  lining  is  not  like  the  ordinary  intima  of  veins.  The  tissue 
of  the  middle  portion  (j)  is  involuntary  muscle  ;  it  is  not  arranged  in  the  usual  manner, 
but  is  disposed  in  large,  separated  bundles,  most  of  which  run  in  the  direction  of  the  length 
of  the  vessel. 


FIG.   17. — SINUS  VENOSUS  OF  THE  HEART.     (X  8.) 

From  the  same  case  as  Fig.  i.  The  vessel  presents  none  of  the  ordinarily  described 
characteristics  of  veins.  It  is  simply  a  channel  through  the  muscular  substance  of  the  heart ; 
the  vessel  has  no  differentiated  wall  except  the  thin  fibrous  layer.  It  is  something  like  the 
vena  cava  represented  by  Figs.  2  and  16. 

FIG.  1 8. — NORMAL  BLOOD-VESSELS  OF  THE  SPINAL  CORD.     (X  50.) 

From  a  man  forty  years  old  who  died  of  tetanus.  The  smaller  thick-walled  vessel  above 
is  an  artery  and  it  is  normal.  The  thin-walled  vessel  below  is  a  vein.  The  striking  feature 
is  that  so  large  a  vein  should  be  simply  a  ring  of  fibrous  tissue  without  any  muscular  layer, 
and  entirely  without  any  division  of  its  walls  into  three  coats. 


FIG.   16. 


:~        X 


FIG.   17. 


FIG.    1 8. 


ARTERIES  AND  VEINS  15 

visible.  The  sinus  venosus  of  the  heart  is  not  like  any  other  blood- 
vessel that  I  have  seen.  Its  wall  is  formed  of  a  fine  thready  tissue 
without  any  trace  of  differentiation  into  coats,  and  there  is  no  involun- 
tary muscle  to  be  distinguished.  This  fine  thready  tissue  forms  the 
only  wall  of  the  vein  and  it  alone  separated  the  blood  from  the  mus- 
cular tissue  of  the  heart  surrounding  the  blood-vessel.  The  vena 
cava  and  sinus  venosus  of  the  heart  are  in  all  respects  different  from 
the  commonly  accepted  conception  of  veins. 

Fig.  1 8  represents  an  artery  and  its  accompanying  vein  of  the 
human  spinal  cord.  The  artery  presents  no  notable  features,  but  the 
vein  shows  in  a  striking  manner  a  peculiarity  that  will  be  further 
emphasized  in  subsequent  chapters.  This  peculiarity  is  that  arterioles 
of  good  size  and  formed  of  three  coats  are  often  accompanied  by  single- 
coated  return  vessels  which  are  much  more  like  very  large  capillaries 
than  like  the  common  veins.  Such  vessels  I  have  found  in  the  heart 
and  in  the  brain  and  spinal  cord.  The  vein  in  Fig.  18  is  formed  en- 
tirely of  fibrous  tissue,  and  it  is  easy  to  see  that  it  does  not  contain 
any  muscular  tissue  in  its  wall  and  that  there  is  no  sign  of  a  division 
into  three  coats.  This  fact — that  the  return  vessels  accompanying 
good-sized  arterioles  often  do  not  have  three  coats — is  mentioned  in 
the  text-books,  but  it  has  not  been  sufficiently  emphasized  to  make  it 
common  knowledge. 


CHAPTER     II 

CAPILLARIES 

CAPILLARIES  are  the  ordinary  channels  of  communication  between 
the  arteries  and  the  veins,  but  under  exceptional  circumstances  the 
arterial  and  venous  radicles  are  said  to  communicate  with  one  another 
directly,  as,  for  instance,  in  the  erectile  tissue  of  the  genital  organs,  in 
the  spleen,  in  the  tips  of  the  fingers  and  toes,  and  in  the  nose.  The 
most  important  function  of  the  capillaries  is  the  distribution  of  the 
nutritive  material  of  the  blood  to  the  tissues.  This  function  is  one  in 
which  the  arteries  and  veins  have  no  share,  for  they  serve  merely  as 
channels  of  communication,  carrying  the  blood  from  one  part  to 
another.  The  capillaries  form  rich  net-works  in  almost  all  of  the 
tissues  and  organs.  Their  average  diameter  is  7—10  microns  and  the 
capillary  supply  of  young  tissues  is  richer  than  that  of  old  ones.  The 
capillaries  generally  consist  of  a  single  layer  of  endothelial  cells,  but 
some  capillaries  are  said  to  be  surrounded  by  an  imperfect  adven- 
titious coat  formed  by  a  net-work  of  branched  connective-tissue  cells. 
The  peculiarities  distinguishing  the  capillaries  from  the  small  capillary 
arteries  and  veins  consist  less  in  the  size  of  the  vessels — for  the  capil- 
laries may  be  the  larger — than  in  the  character  of  their  walls.  The 
true  capillary  possesses  no  muscle-cells.  Such  is  the  ordinarily  ac- 
cepted description  of  the  objective  features  of  the  capillaries.  In 
thinking  of  them  the  fact  must  never  be  lost  sight  of  that  they  are  the 
only  part  of  the  blood-vessels  that  is  directly  occupied  in  fulfilling  the 
primary  function  of  the  circulatory  apparatus,  namely,  the  nutrition  of 
the  tissues.  The  arteries  and  veins  are  only  tubes  to  carry  the  fluid 
from  place  to  place  in  the  economy.  The  anatomy  and  pathology  of 
the  arteries  and  veins  are  easy  studies  in  comparison  with  that  of  the 
capillaries,  for  arteries  and  veins  are  permanent  and  are  large  enough 
to  be  easily  seen,  while  of  the  capillaries  it  may  without  exaggeration 
be  said  that  they  are  ephemeral  and  elusive.  There  is  a  certain 
likeness  between  the  human  vascular  system,  composed  of  the  heart, 
the  arteries,  the  veins,  and  the  capillaries,  and  the  rain  when  it  falls 
upon  the  earth  and  runs  off  to  the  sea  in  rills,  rivulets,  and  rivers. 
If  any  profit  is  to  be  derived  from  the  comparison,  however,  allow- 
16 


CAPILLARIES  17 

ance  must  be  made  for  the  great  difference  of  the  forces  at  work 
and  the  widely  different  conditions.  Gravity  is  the  force  which  carries 
the  rain-water  to  the  sea,  whereas  it  is  the  pumping  action  of  the  heart 
which  drives  the  blood  through  the  arteries  into  the  capillaries.  When 
the  rain  falls  upon  the  earth  the  flow  is  from  the  smaller  into  the 
larger  channels,  but  the  blood  is  driven  from  the  large  arteries  into 
the  minute  capillaries.  Conceding  the  difference,  I  think  the  resem- 
blance is  striking.  When  it  rains  the  drops  collect  together  until  a 
body  of  water  is  formed  which  is  too  large  to  lie  upon  the  surface 
where  it  has  fallen,  the  water  then  flows  out  in  the  direction  in  which 
the  ground  falls,  forming  a  little  rill.  The  rill  flows  on  until  it  meets 
with  others  like  itself,  with  which  it  joins  and  they  go  on  until  a 
permanent  stream  is  reached,  and  every  one  knows  how  streams  run 
together,  growing  larger  and  larger  until  a  river  is  formed.  The  riv- 
ers and  the  larger  streams  are  permanent  and  they  are  perhaps  the 
most  striking  of  nature's  features  ;  but  the  little  rills  disappear  after 
every  rain  and  the  smaller  ones — in  the  grass,  for  instance — leave  no 
trace  behind  to  show  where  they  were.  Arteries  and  veins  and 
arterioles  and  venules  are  as  permanent  as  the  rivers  and  streams. 
Even  if  disease  forms  an  obstruction  and  blocks  up  one  of  these 
larger  blood-vessels,  the  empty  one  continues  to  have  as  distinctive  a 
form  of  its  own  and  is  as  easy  to  recognize  as  a  stream  bed  from 
which  the  water  has  been  turned  aside.  The  capillaries  are  like  the 
rills,  for  they  come  and  go.  They  may  truly  be  said  to  be  ephemeral, 
for  they  open  in  the  tissues  as  the  need  for  them  arises  and  close  and 
disappear  when  their  usefulness  has  ceased.  The  importance  of  this 
obvious  truth  has  not  been  fully  recognized,  for,  although  pathologists 
have  studied  the  growth  of  capillaries  under  the  influence  of  disease 
in  tissues  like  the  cornea,  the  converse  of  the  proposition,  that  they 
are  evanescent,  has  not  been  dwelt  upon  to  make  the  fact  seem  as 
important  as  it  really  is. 

The  ordinary  description  of  a  capillary  is  that  it  is  a  minute  tube 
composed  of  a  single  layer  of  endothelium.  Endothelium  is  like 
a  pavement  of  tiles,  being  formed  of  a  single  layer  of  flat  cells  which 
are  accurately  joined  together  at  their  edges.  Capillaries  are  so 
small  that  they  can  be  seen  only  with  the  microscope.  Most  of 
the  human  tissues  contain  capillaries,  but  there  are  none  in  the  nails, 
the  outer  horny  layer  of  the  skin,  the  enamel  of  the  teeth,  and  the 


l8  HUMAN  BLOOD-VESSELS 

healthy  cornea  of  the  eye.  Although  capillaries  are  present  in  most 
of  the  tissues,  it  is  not  always  possible  to  distinguish  them  in  unin- 
jected  specimens  after  death.  In  sections  which  have  been  prepared 
by  the  ordinary  methods  the  capillaries  are  generally  visible  in  the 
heart  and  very  often  they  are  easily  seen  in  sections  of  the  lung.  In 
the  liver  and  spleen  they  are  generally  less  readily  made  out,  and  in 
the  kidney  sometimes  they  are  very  obvious  and  again  it  is  hard  to  see 
any  of  them. 

In  properly  prepared  sections  of  suitable  specimens  of  human 
heart  large  groups  of  capillaries  branching  in  the  most  complex  way 
may  be  seen  with  the  greatest  distinctness.  They  are  seen  in  longi- 
tudinal and  in  cross-section,  so  that  the  demonstration  that  they  are 
tubes  is  perfectly  complete  and  satisfactory,  and,  as  blood-corpuscles 
are  often  seen  lying  in  many  of  the  capillaries,  the  anatomical  picture 
is  complete.  When  it  is  remembered,  however,  that  the  walls  of  these 
tubes  are  exceedingly  delicate  and  besides  that  all  connective  tissue 
contains  exactly  similar  cells,  it  raises  the  doubt  whether  the  capilla- 
ries are  any  more  permanent  than  the  rills  of  water  that  run  through 
the  grass  during  a  rain.  How  can  a  capillary  be  recognized  with 
certainty  in  any  ordinary  section  of  tissue  ?  Only  by  its  size,  circu- 
lar opening,  and  wall  composed  of  a  single  layer  of  endothelium 
with  the  characteristic  nuclei.  If  in  addition  to  this  a  few  blood-cor- 
puscles in  such  a  state  of  preservation  as  to  make  it  certain  they  are 
blood-corpuscles  are  lying  within  the  calibre,  the  demonstration  is 
complete.  Such  are  typical  capillaries  and  they  are  easy  to  see  in 
sections  of  human  heart  and  often  in  other  tissues.  When  seen  in 
this  form  there  can  be  no  doubt  as  to  what  they  are,  and  that  they 
are  as  definite  entities  as  the  largest  artery  or  vein.  If  a  moment  is 
given  to  the  consideration  of  the  surroundings  of  the  ordinary  capil- 
laries in  the  heart,  it  will  be  manifest  that  capillaries  must  often 
be  very  elusive  objects  to  search  for  with  the  microscope.  Most 
of  the  capillaries  lie  in  the  interstices  between  the  bundles  of 
muscular  fibres,  and  these  interstices  are  filled  with  connective  tissue. 
Even  when  the  capillaries  penetrate  into  the  narrowest  spaces  be- 
tween single  muscular  fibres  and  into  the  very  centres  of  the  fibres 
themselves,1  a  little  connective  tissue  appears  always  to  accompany 
them. 

'Origin  of  Disease,  by  Arthur  V.  Meigs,  Chapter  V.  :     J.  B.  Lippincott  Co.,  1899. 


CAPILLARIES  19 

If  a  bundle  of  capillaries  in  the  heart  could  be  emptied  of  blood 
and  then  exposed  to  sufficient  pressure  to  force  the  capillary  walls 
together,  the  tissue  would  look  exactly  like  any  of  the  ordinary  con- 
nective tissue  which  lies  in  the  intermuscular  spaces  of  the  heart. 
Almost  exactly  the  same  is  the  case  with  the  capillaries  of  the  other 
organs  and  tissues.  Wherever  capillaries  go  they  lie  in  the  connec- 
tive-tissue spaces,  and  even  when  a  capillary  is  seen  by  itself  it  is 
found  to  be  accompanied  by  some  connective  tissue.  It  is  hardly  con- 
ceivable that  under  the  constantly  varying  conditions  of  the  circulation 
and  the  changes  to  which  the  tissues  are  subject  the  bundles  of  capil- 
laries do  not  often  become  empty,  and  if  they  do  become  empty  they 
must  collapse,  as  other  tubes  in  the  human  body  do  when  there  is 
nothing  within  them  to  hold  them  open.  When  a  bundle  of  capillaries 
is  emptied  and  the  walls  fall  together,  their  calibres  must  very  soon  be 
obliterated.  From  what  is  known  of  the  tendency  of  the  tissues  to 
adhere  when  they  are  wounded,  it  is  only  reasonable  to  think  that 
obliteration  must  soon  occur ;  besides  which  the  axiom  that  nature 
abhors  a  vacuum  would  be  almost  enough  to  make  it  certain  that  a 
series  of  collapsed  tubes  would  not  long  remain  patulous.  It  is  certain 
that  capillaries  are  ephemeral  and  often  return  to  their  primitive  state 
by  giving  back  their  walls  again  to  form  simple  connective  tissue  ;  it  is 
also  certain  that  they  can  push  their  way  on,  and  form  and  increase 
in  tissues  in  which  they  had  not  been,  for  this  process  has  often  been 
watched  under  the  microscope  in  living  animals.  It  is  my  opinion 
that  capillaries  never  have  the  same  definite  existence  that  arteries 
and  veins  have.  The  arteries  and  veins  are  sharply  differentiated, 
having  a  special  structure  of  their  own,  and  they  must  always  be 
built  up  in  any  tissue  in  which  they  lie.  The  capillaries,  on  the  other 
hand,  are  nothing  but  tubes  hollowed  out  in  the  connective  tissue 
with  which  they  are  surrounded.  If  a  single  capillary  running  in 
any  tissue  by  itself  is  empty,  it  becomes  at  once  and  without  any 
change  a  string  or  fibre  of  connective  tissue. 

This  belief  that  capillaries  are  evanescent  and  never  have  the  same 
permanent  and  definite  existence  as  arteries  and  veins  is  supported 
by  the  study  of  injected  specimens  of  various  tissues.  In  properly 
selected  specimens  of  tissue  of  which  the  blood-vessels  are  injected, 
it  is  easy  to  see  the  capillaries.  If  one  color  is  used  to  dye  the  in- 
jected material  and  another  for  staining  the  tissue,  the  contrast  of  the 


20 


HUMAN  BLOOD-VESSELS 


two  colors  causes  the  blood-vessels  to  be  striking  objects  in  any  field 
which  is  examined  under  the  microscope.  Injected  specimens,  how- 
ever, do  not  give  the  perfect  satisfaction  that  it  might  be  hoped  they 
would,  and  this  is  principally  for  two  reasons  :  first,  that  the  colored 
injection  material  necessarily  partly  covers  and  therefore  obscures  por- 
tions of  the  tissue  which  in  uninjected  specimens  of  the  same  tissue 
are  easily  seen  ;  and,  second,  because  it  is  often  impossible  to  know 
whether  a  particular  portion  of  the  injected  material  that  is  being 
examined  is  really  within  a  blood-vessel  or  if  the  vessel  has  burst  and 
this  material  is  lying  loose  in  the  tissue.  The  manner  in  which  an 
injected  liquid  distributes  itself  in  some  tissues  clearly  shows  how 
capillary  channels  may  open  in  the  same  tissue  during  life  when  there  is 
need  for  them.  In  examining  sections  of  injected  tissues,  it  is  always 
easy,  if  one  is  disposed  to  be  careless,  to  say  of  any  appearance  that 
is  difficult  to  interpret  that  it  resulted  from  the  bursting  of  the  blood- 
vessels owing  to  too  great  force  having  been  used  in  making  the  injec- 
tion, and  that  the  injected  liquid  had  escaped  into  the  interstices  of 
the  tissue.  There  is  no  doubt  that  in  making  injections  this  accident 
often  occurs.  Under  these  circumstances  the  liquid  of  course  flows  in 
the  direction  of  least  resistance  and  it  fills  the  portions  of  tissue  which 
are  most  open-meshed  and  loosely  constructed.  The  lesson  which 
should  be  learned  from  this  is,  I  think,  that  very  much  the  same  thing 
may  happen,  and  probably  often  does  happen,  during  life  in  condi- 
tions of  disease  that  can  be  produced  after  death  by  the  use  of  a 
syringe  to  force  fluid  into  the  blood-vessels. 

Sections  of  human  spleen  sometimes  present  appearances  which 
lend  support  to  the  belief  that  capillaries  are  ephemeral,  and  are  simply 
openings  in  the  tissue,  permitting  the  passage  of  blood,  instead  of  being 
differentiated  vascular  channels  with  distinct  walls,  as  the  arteries  and 
veins  are  known  to  be.  As  has  already  been  said,  it  is  difficult  to  draw 
an  absolutely  just  comparison  between  the  conditions  which  exist 
during  life  and  post-mortem  appearances  and  effects  that  result  from 
the  manipulation  of  dead  tissues.  When  the  size  of  a  channel  or 
space  which  has  been  filled  with  injecting  fluid  is  being  considered, 
and  it  is  desirable  to  know  whether  this  channel  or  space  was  of  the 
same  size  during  life,  the  knowledge  cannot  be  obtained.  It  has  been 
already  shown  that  shrinking  always  occurs  at  the  time  of  death  when 
the  blood-vessels  empty  themselves,  and  that  there  is  further  shrinkage 


CAPILLARIES  21 

afterwards  in  the  course  of  manipulation  in  preparing  the  tissue  for 
microscopical  examination.  It  is  impossible  to  form  an  estimate  which 
can  be  known  to  be  anything  like  accurate  in  regard  to  the  extent  of 
this  shrinkage,  and  therefore  it  is  impossible  to  know  what  was  the 
size  during  life  of  any  blood  space  that  is  examined  after  death. 

In  sections  of  human  spleen  injected  with  a  blue  dye  and  stained 
red  with  carmine,  areas  are  often  seen  in  which  the  leucocytes  which 
are  stained  red  are  surrounded  by  fine  threads  of  the  blue  injecting 
material.  The  result  is  that  the  leucocytes  are  spherical  or  polyhedral 
and  are  not  directly  in  contact,  but  are  separated  by  a  fine  mesh-work 
of  spaces  or  channels  which  are  filled  by  the  blue  injecting  material. 
The  red  leucocytes  are  often  completely  surrounded  by  the  rings  of 
blue.  In  order  to  see  this  it  is  necessary  to  use  quite  high  amplifica- 
tion, and  it  is  impossible  to  be  certain  whether  the  spaces  that  the  in- 
jecting material  has  filled  have  walls,  and  therefore  answer  the  classical 
description  of  capillaries,  or  if  the  injection  was  forced  between  the  cells 
and  lies  there  without  anything  to  separate  it  from  the  cells  them- 
selves. In  any  blood-vessel  which  has  been  injected,  even  in  large 
ones  like  arteries  and  veins,  the  walls  cannot  be  so  well  studied  as  in 
uninjected  specimens,  because  the  injection  material  always  partially 
covers  up  the  tissue  of  the  walls  and  obscures  the  view  of  them.  In 
the  case  of  injected  capillaries  the  walls  often  cannot  be  seen  at  all 
and  they  are  always  much  obscured.  The  intercellular  spaces  in  in- 
jected spleen,  that  have  been  described  as  being  filled  by  the  injecting 
material,  are  often  much  narrower  than  an  ordinary  capillary  and  are 
so  small  that  it  would  have  been  quite  impossible  for  a  blood-corpuscle 
to  have  passed  through  them.  The  appearance  of  the  splenic  leuco- 
cytes stained  of  one  color  and  surrounded  by  the  fine  and  often  very 
complete  mesh-work  of  the  injection  material  of  a  different  color  is 
very  striking,  and  it  makes  it  seem  highly  probable  that  fluids  pass 
around  the  leucocytes  during  life,  but  it  is  impossible  to  know  whether 
there  are  simply  intercellular  spaces  or  if  there  is  a  net-work  of  capil- 
lary tubes  with  walls  of  their  own. 

It  is  easy  for  any  one  to  suggest,  as  an  explanation  of  the  appear- 
ance that  has  been  described,  that  the  injection  had  burst  the  capil- 
laries and  that  the  injecting  material  had  escaped  into  the  interstices 
of  the  tissue,  but  it  is  impossible  to  prove  that  such  was  the  case. 
There  is  no  reason  why  the  heart  may  not  drive  fluid  almost  any- 


22  HUMAN  BLOOD-VESSELS 

where  that  it  can  be  forced  with  a  syringe.  It  seems  to  me  reason- 
able to  think  that  the  interstices  between  the  splenic  leucocytes  are 
connected  with  the  blood  stream  during  life,  and,  if  the  spaces  are  too 
small  to  permit  the  passage  of  the  blood-corpuscles  through  them, 
that  the  liquor  sanguinis  in  this  way  bathes  the  splenic  cells.  Al- 
though the  splenic  intercellular  interstices  as  they  are  seen  post 
mortem  in  injected  tissue  are  of  much  less  diameter  than  a  blood- 
corpuscle,  it  is  impossible  to  be  sure  that  this  is  not  owing  simply  to 
post-mortem  shrinkage,  and  that  during  life  the  cells  of  the  spleen  are 
at  all  times  sufficiently  widely  separated  to  permit  of  the  passage 
between  them  of  the  blood-corpuscles.  I  have  many  sections  of 
injected  human  spleen  which  demonstrate  the  characteristics  described, 
and  I  have  often  thought  of  having  a  picture  made  showing  the  con- 
ditions, but  I  have  been  deterred  because  of  the  difficulties.  Such  a 
picture  would  have  to  be  in  two  colors,  and,  as  the  red  leucocytes  and 
the  surrounding  threads  of  blue  can  be  seen  only  when  greatly  magni- 
fied and  with  changes  of  the  focus  of  the  microscope,  it  would  be  very 
difficult  to  get  an  artist  to  appreciate  the  conditions  and  then  to 
depict  them.  The  following  quotation  from  Leidy's  Anatomy  shows 
that  the  belief  in  the  existence  of  capillary  spaces  too  minute  to 
admit  of  the  passage  of  a  blood-corpuscle  is  not  incompatible  with 
opinions  formerly  accepted  as  correct.  "The  smallest  admit  the  pas- 
sage of  blood-corpuscles,  although  but  a  short  time  has  elapsed  since 
the  opinion  universally  prevailed  that  in  all  structures  of  the  body 
capillaries  existed  which  only  transmitted  the  liquor  sanguinis."  1 

In  the  following  chapters  various  curious  conditions  of  capillaries 
caused  by  disease  are  described.  In  pathology  the  question  how 
far  Gull  and  Sutton,  in  their  classical  essays  on  arteriocapillary 
fibrosis,  were  correct  in  supposing  that  the  disease  they  described  is 
really  one  of  vascular  origin  is  of  perennial  interest  and  is  not  even 
yet  decided.  If  the  capillaries  are  as  ephemeral  as  I  believe,  and 
their  walls  are  only  cylindrical  channels  which  come  and  go  from  day 
to  day  in  the  connective  tissues,  it  becomes  a  question  whether  the 
diseases  that  affect  them  originate  in  the  blood  or  in  the  connective 
tissue.  The  study  of  disease  of  the  capillaries  is  therefore  a  very 
difficult  one,  and  but  little  has  yet  been  learned  regarding  it. 

1  An  Elementary  Treatise  on  Human  Anatomy,  by  Joseph  Leidy  :  J.  B.  Lippincott  &  Co., 
1861,  page  337. 


CHAPTER    III 

NEW  BLOOD-VESSELS 

IT  has  long  been  known  that  new  blood-vessels  develop  in  the 
tissues  under  the  stimulus  of  disease,  and  that  this  new  growth  takes 
place  even  in  aged  people  in  the  same  manner  that  it  does  in  the 
young.  Ziegler1  says,  "The  formation  of  new  blood-vessels  plays  a 
chief  part  in  hyperplasias  of  ever}''  kind.  Wherever  fibrous  tissue, 
bone-tissue,  gland-tissue,  or  any  other  is  produced  in  quantity,  new 
blood-vessels  must  of  necessity  be  developed.  In  no  other  way  is  it 
possible  to  keep  the  new-formed  tissue  adequately  supplied  with 
nutriment.  For  this  reason  new  blood-vessels  begin  to  be  formed  at 
a  very  early  stage  in  all  new  growths,  and  they  must  be  regarded  as 
the  chief  factors  in  the  formative  process. 

"  New  blood-vessels  are  developed  out  of  offshoots  which  start  from 
the  walls  of  existing  blood-vessels.  .  .  .  We  have  not  given 
the  customary  enumeration  of  the  primary,  secondary,  and  tertiary 
modes  formulated  by  Billroth  and  Rindfleisch.  In  the  primary  mode 
the  embryonic  cells  become  directly  transformed  into  red  blood-cells 
on  one  hand,  and  into  the  parietal  cells  of  a  vessel  on  the  other.  The 
embryonic  cells  in  fact  arrange  themselves  into  cords :  the  axial  ones 
become  blood-cells,  the  peripheral  ones  cohere  as  elements  of  the 
containing  vessel-wall.  This  process  takes  place  in  the  mesoblast  of 
the  embryo,  but  not  in  pathological  formations."  Ziegler's  descrip- 
tion of  the  secondary  mode  is  not  quite  clear,  but  he  describes  it  as 
not  very  different  from  the  primary  one.  He  then  goes  on  to  describe 
the  tertiary  mode,  giving  a  concise  account  of  what  is  so  well  known 
of  the  development  of  blood-vessels  under  the  stimulus  of  irritation  in 
the  cornea  of  the  eye,  in  the  web  of  the  frog's  foot,  in  the  tadpole's 
tail,  etc.  An  important  point  to  note  is  his  statement  that  "  new 
blood-vessels  are  developed  out  of  offshoots  which  start  from  the  walls 
of  existing  blood-vessels,"  and  that  after  discussing  the  independent 
growth  of  blood-vessels,  which  is  so  well  known  and  has  been  so 

1  Text- Book  of  Pathological  Anatomy,  by  Ernst  Ziegler,  translated  by  Donald  MacAlister. 
Part  i,  General  Pathological  Anatomy,  pages  125-127.  London,  Macmillan,  1883. 

23 


24  HUMAN  BLOOD-VESSELS 

minutely  observed  in  the  tissues  of  embryos,  he  says,  "this  process 
takes  place  in  the  mesoblast  of  the  embryo,  but  not  in  pathological 
formations."  These  conclusions  of  Ziegler  constitute  a  fair  exposition 
of  the  opinions  that  prevail  in  regard  to  the  development  of  new 
blood-vessels  as  a  result  of  disease.  There  cannot  be  the  slightest 
doubt  that  his  views  are  correct  as  far  as  concerns  the  mode  of  growth 
by  offshoots,  which  has  been  studied  with  such  scientific  exactitude 
that  the  results  which  have  been  obtained  are  conclusive.  It  has 
seemed  to  me,  however,  that  Billroth  and  Rindfleisch  were  right  in  their 
belief  that  when  the  conditions  necessary  to  its  production  exist  the 
same  kind  of  development  of  blood-vessels  that  is  known  to  take 
place  in  embryos  occurs  also  in  pathological  formations.  It  is  not 
possible  to  prove  the  correctness  of  this  opinion  in  the  same  way  that 
it  has  been  proved  that  blood-vessels  grow  from  offshoots,  for  that 
mode  of  development  can  be  made  to  take  place  at  will  in  the  tissues 
of  animals  and  all  the  various  stages  of  the  process  can  be  closely 
watched.  On  the  other  hand,  the  only  evidence  that  can  be  obtained 
to  prove  that  blood-vessels  grow  independently  of  the  pre-existing 
ones  in  pathological  formations,  in  the  same  way  that  they  grow  in 
embryos,  must  be  acquired  from  the  examination  of  diseased  tissues 
after  death.  As  progress  ceases  with  death,  there  is  no  opportunity 
to  see  the  course  of  growth. 

It  is  not  unnatural  for  those  who  have  studied  the  growth  of  new 
vessels  in  the  tissues  of  the  lower  animals,  a  process  they  can  set  in 
motion  at  will  and  thereby  at  any  time  obtain  abundant  material  for 
study,  to  be  slow  to  believe  that  blood-vessels  grow  independently  in 
diseased  tissues  in  the  same  way  that  they  grow  in  embryos.  It  is 
impossible,  as  has  been  said,  to  prove  that  they  do,  but  I  have  some 
specimens  of  tissue  which  present  appearances  which  I  think  make  it 
reasonable  to  believe  that  blood-vessels  do  grow  independently.  The 
tissue  in  which  I  have  been  able  to  study  this  development  of  blood- 
vessels to  the  greatest  advantage  is  the  thickened  intima  of  arteries 
which  have  been  affected  by  endarteritis.  It  often  happens  that  the 
three  tunics  can  still  be  easily  distinguished  even  in  arteries  which  are 
exceedingly  thick,  in  properly  prepared  sections.  The  coat  which  is 
ordinarily  the  most  diseased  and  thickened  is  the  intima,  and  it  is 
often  composed  of  a  material  which  is  unlike  any  of  the  natural 
tissues.  In  some  respects  this  tissue  resembles  connective  tissue  and 


NEW  BLOOD-VESSELS  25 

in  others  it  is  not  unlike  ill-developed  epithelium.  It  is  in  tissue  of 
this  nature  especially  that  I  have  seen  the  most  curious  and  varied 
forms  of  new  blood-vessels.  It  may  be  well  to  recall  the  fact  that 
in  the  natural  condition  the  vasa  vasorum  are  confined  to  the  external 
coat  of  the  arteries  and  veins  they  nourish,  and  that  none  of  them 
penetrate  into  the  muscular  tunic,  nor  are  any  to  be  found  in  the 
intima. 

In  a  set  of  serial  sections  of  an  arteriole  from  the  lung  of  a  child 
twelve  years  old,  who  died  of  heart  disease,  I  have  found  the  most 
convincing  evidence  of  the  independent  growth  of  blood-vessels. 
The  artery  is  greatly  thickened,  but  the  plicated  membrane  can  be 
distinctly  seen  around  the  entire  arterial  circle.  As  usual  this  mem- 
brane is  a  valuable  landmark,  making  it  possible  clearly  to  distinguish 
one  coat  from  another.  In  this  arteriole  the  intima  is  much  thicker 
than  either  of  the  other  coats,  and  it  is  composed  of  the  peculiar  tissue 
which  has  already  been  mentioned  as  difficult  to  classify,  for  it  has 
some  of  the  characteristics  of  connective  tissue  and  some  of  those  of 
epithelium,  and  yet  presents  marked  differences  from  them  both. 
This  curious  growth  is  more  like  the  tissue  which  is  seen  in  early  em- 
bryos than  like  anything  else.  All  embryologists  know  that  during 
the  early  stages  of  development  the  cells  in  the  tissues  of  embryos 
are  unlike  any  cells  of  the  tissues  or  organs  of  adults  and  are  without 
the  distinctive  characteristics  that  they  acquire  later.  For  instance, 
the  difference  of  the  heart  from  the  liver  is  to  be  distinguished  by  the 
form  and  position  of  the  two  organs  and  not  by  the  differences 
between  the  muscle  cells  of  the  heart  and  the  epithelial  cells  of  the 
liver  which  in  adult  life  are  so  great.  In  this  arteriole  of  which  the 
intima  is  so  thick  and  is  formed  of  tissue  like  that  of  embryos,  there 
are  spaces  which  are  like  the  blood-islands  which  develop  in  the  vas- 
cular area  outside  the  body  of  the  embryo  of  the  chick  and  which  are 
at  first  independent  and  disconnected  from  the  heart.  By  examining 
these  spaces  through  several  of  the  serial  sections  it  is  easy  to  deter- 
mine that  they  answer  the  descriptions  of  the  blood-islands  of  em- 
bryos and  they  contain  cells  which  closely  resemble  blood-corpuscles. 
As  the  tissue  is  pathological,  and  as  it  is  never  possible  to  obtain  the 
tissues  of  those  who  die  of  disease  in  a  fresh  condition  as  is  always 
done  by  embryologists  in  pursuing  their  researches,  it  would  probably 
be  unreasonable  to  expect  to  get  the  nearly  perfect  results  that  em- 


26  HUMAN  BLOOD-VESSELS 

bryologists  obtain.  If  it  is  impossible  to  be  certain  that  the  cells  con- 
tained by  these  blood-islands  are  blood-corpuscles,  it  is  easy,  on  the 
other  hand,  to  determine  that  the  spaces  are  closed  sacs  and  quite 
disconnected  from  the  blood-vessels.  A  study  of  the  serial  sections 
demonstrates  that  the  spaces  are  not  connected  with  any  blood-vessels 
nor  with  anything  else,  but  are  independent.  The  spaces  are  too 
large  to  be  swollen  cells,  and  it  seems  impossible  to  explain  their 
existence  in  any  other  way  than  to  say  that  they  are  developing 
blood-vessels,  with  all  the  characteristics  of  the  earliest  developed 
blood-vessels  of  embryos  which  grow  in  the  vascular  area  and  else- 
where independently  of  the  heart  and  aorta  and  are  aftenvards  joined  to 
them.  It  is  certain  the  spaces  I  have  described  are  disconnected  from 
the  general  vascular  system,  and  if  it  could  be  proved  that  they  are 
blood-vessels  it  would  establish  the  fact  that  I  am  correct  in  my  conten- 
tion that  new  blood-vessels  develop  in  diseased  adult  tissues  in  the  same 
way  that  they  develop  in  embryos,  and  not,  as  has  been  generally 
believed  of  late,  by  the  process  of  offshoots  alone.  I  have  already 
described  these  sections,1  and  have  published  illustrations  exhibiting 
their  peculiarities,  and  I  had  at  one  time  the  intention  to  have  another 
series  of  drawings  made  to  demonstrate  still  more  completely  the 
presence  of  the  blood-islands  in  the  morbidly  thickened  intima,  but  I 
found  that  it  would  be  difficult  or  impossible.  In  studying  sections, 
and  especially  serial  sections,  with  the  microscope,  one  often  arrives 
at  an  opinion  which  is  the  result  of  the  examination  of  many  sections 
and  the  consideration  of  the  relations  of  the  appearances  of  one  sec- 
tion with  those  of  others.  Such  opinions  cannot  always  be  supported 
by  pictures  of  the  tissues  that  have  been  studied. 

New  blood-vessels  develop  in  tumors  and  in  every  new  tissue  which 
is  produced  as  a  result  of  disease.  Such  tissue  is  beyond  doubt  a 
new  production  and  cannot  justly  be  regarded  as  the  result  of  exten- 
sion or  outgrowth.  New  vessels  grow  in  the  walls  of  aneurisms, 
which  might  be  considered  to  be  mere  extensions  of  natural  tissue, 
but  the  increased  amount  of  tissue  that  is  formed  in  large  saccular 
aneurisms  makes  it  seem  .  more  reasonable  to  regard  as  a  real  new 
growth  the  material  constituting  their  walls.  In  all  of  these  tissues 
new  blood-vessels  may  be  found  which  present  a  great  variety  of 

1  Origin  of  Disease,  by  Arthur  V.  Meigs,  ad  edition,  page  52  et  seq.,  and  Figs.  23  to  27  : 
J.  B.  Lippincott  Co. ,  Philadelphia,  1890. 


NEW  BLOOD-VESSELS  27 

appearances,  and  it  has  long  seemed  to  me  that  the  most  reasonable 
hypothesis  in  regard  to  their  mode  of  growth  is  that  many  of  them 
originated  independently  of  the  vessels  already  existing  in  the  sur- 
rounding tissues  and  that  they  were  later  joined  to  the  general  system 
of  blood-vessels  in  exactly  the  same  manner  as  happens  in  embryos. 
In  my  book  on  "The  Origin  of  Disease"  there  are  descriptions  and 
illustrations  of  blood-vessels  in  the  new  growth  of  pericardial  adhe- 
sions l  and  in  the  wall  of  an  aneurism.2 

There  are  many  other  curious  and  interesting  facts  connected  with 
the  development  of  new  blood-vessels.  In  the  earlier  stages  of  their 
existence  and  while  they  are  still  small,  they  more  nearly  resemble 
capillaries  than  arteries  or  veins.  Their  walls  are  composed  of  fine 
fibrous  material  containing  endothelial  nuclei,  and  there  is  no  muscu- 
lar layer  nor  any  adventitia.  The  new  vessels  frequently  acquire  a 
considerable  size  and  still  retain  this  capillary  formation,  but  the 
thickness  of  the  walls  varies  much  with  the  difference  in  size  of  the 
vessel.  Although  new  blood-vessels  often  have  single-coated  walls 
of  fibrous  tissue,  even  after  they  attain  considerable  size,  they  are 
capable  of  the  further  development  of  producing  three  coats  in  all 
respects  like  normal  arteries. 

Fig.  19  represents  an  arteriole  in  the  peduncle  which  attached  a 
small  fatty  tumor  to  the  liver.  The  tumor  lay  upon  the  upper  sur- 
face of  the  liver,  between  that  organ  and  the  diaphragm.  The  vessel 
has  three  coats  like  any  normal  arteriole,  and  the  muscular  cells  of 
both  the  longitudinal  and  circular  layers  are  distinctly  shown.  It  is 
as  certain  as  anything  in  pathology  can  be  that  this  arteriole  is  a  new 
growth,  for  a  fatty  tumor  loosely  attached  to  the  upper  surface  of  the 
liver,  with  such  an  arteriole  passing  through  the  peritoneal  covering 
upon  the  free  surface  of  the  liver  and  going  to  nourish  the  tumor, 
could  only  be  the  result  of  diseased  new  growth.  The  discovery 
even  of  one  three-coated  arteriole  of  normal  appearance  is  sufficient 
to  show  that  the  capacity  to  develop  natural  blood-vessels  under  the 
stimulus  of  disease  remains  until  past  middle  life.  The  man  from 
whom  this  arteriole  was  taken  was  fifty-two  years  old,  and  it  is  most 
likely  that  the  capacity  to  develop  new  blood-vessels,  even  fully 

1  Origin  of  Disease,  page  51  and  Figs.  18,  19,  and  20. 
1  Origin  of  Disease,  Fig.  15. 


28  HUMAN  BLOOD-VESSELS 

formed    arteries    and  veins,  is  retained   by  human   beings    even    to 
extreme  old  age. 

Fig.  20  is  a  blood-vessel  from  the  spinal  cord  of  a  boy  of  fifteen 
years  who  died  of  simple  meningitis.  The  appearances  and  the 
pathological  changes  of  the  blood-vessels  in  simple  and  in  tubercular 
meningitis  and  in  syphilis  will  be  discussed  in  another  chapter  (page 
69).  The  vessel  represented  is  so  much  altered  by  disease  that  it  is 
impossible  to  ascertain  whether  it  is  an  artery  or  a  vein,  but  it  is  very 
much  more  probably  an  artery,  for  arteries  frequently  become  thick 
walled  as  a  result  of  disease,  and  veins  are  comparatively  seldom 
affected  in  the  same  way.  The  tissue  composing  this  blood-vessel 
(Fig.  20)  is  not  like  that  which  forms  healthy  vessels,  and  nothing  can 
be  seen  of  the  normal  division  of  the  wall  into  three  coats.  There  is 
no  involuntary  muscular  tissue,  nor  anything  like  the  natural  intima 
or  like  the  tissue  which  commonly  forms  the  thickened  intima  of 
diseased  arteries.  I  do  not  know  of  anything  in  healthy  human  beings 
like  this  tissue,  but  it  in  some  respects  resembles  that  of  embryos. 
The  most  striking  feature,  however,  and  the  feature  that  the  drawing 
was  made  to  show,  is  that  there  are  numerous  new  blood-vessels  in 
the  thickened  wall  of  the  diseased  vessel.  These  new  blood-vessels, 
as  is  usually  the  case  with  small  new  blood-vessels,  are  like  capil- 
laries, and  quite  a  number  of  them  contain  blood-corpuscles.  The 
appearance  of  these  small  new  capillaries  containing  blood-corpuscles, 
and  the  nature  of  the  tissue  which  forms  the  wall  of  the  whole  blood- 
vessel, strongly  resembles,  I  think,  the  blood-islands  that  are  found  in 
embryos,  and  that  are  so  easy  to  see  in  the  area  vasculosa  outside  of 
the  body  of  the  developing  chick  embryo.  This  supports  the  opinion 
I  have  already  expressed,  that  new  blood-vessels  grow  in  human  tis- 
sues in  disease  separately  from  the  vascular  system  and  are  afterwards 
joined  to  it,  as  occurs  in  embryos,  and  do  not  grow  solely  as  offshoots 
from  pre-existing  blood-vessels,  as  is  generally  believed. 

It  is  very  common  for  new  blood-vessels  to  grow  in  and  about  the 
capsules  of  the  thoracic  and  abdominal  viscera,  and  such  vessels  are 
shown  by  Figs.  21,  22,  23,  and  24.  Fig.  21  depicts  a  portion  of  the  free 
edge  of  the  lung  of  a  negro  man  forty-nine  years  old,  who  died  of 
Bright's  disease.  The  tissue  of  the  lung  is  thickened  and  unnatural 
in  appearance,  owing  to  the  action  of  slow  inflammatory  fibrocellular 
infiltration.  The  pleura  is  incorporated  with  the  diseased  lung-tissue 


FIG.   19. — NEW  ARTERIOLE.     (X  240.) 

From  a  man  of  fifty-two  years  who  died  of  chronic  ulceration  of  the  rectum.  The  vessel 
is  in  the  peduncle  of  a  small  fatty  tumor  which  lay  upon  the  upper  and  outer  surface  of  the 
liver,  to  which  it  was  fastened  by  the  peduncle.  The  peculiarity  of  this  vessel  is  that  it  is 
exactly  like  small  normal  arterioles,  instead  of  having  walls  composed  of  endothelium  or 
fibrous  tissue  alone,  as  most  new  vessels  seen  in  diseased  tissues  have.  The  cells  of  the 
involuntary  muscle  are  distinctly  shown,  some  of  them  in  cross  and  some  in  longitudinal 
section. 


FIG.  20. — THICKENED  BLOOD-VESSEL  OF  THE  SPINAL  CORD,  WITH   NUMEROUS  CAPIL- 
LARIES IN  ITS  WALL.     (X  240.) 

From  a  boy  fifteen  years  old  who  died  of  acute  meningitis.  It  is  impossible  to  ascertain 
whether  the  vessel  is  an  artery  or  a  vein,  it  is  so  much  changed  by  disease.  The  wall  is 
very  thick,  and  there  are  many  capillaries  in  it  which  contain  blood-corpuscles.  A  few 
blood-corpuscles  are  lying  in  the  lumen  of  the  vessel  adhering  to  its  lining. 


FIG.   19. 


FIG.  20. 


NEW  BLOOD-VESSELS  29 

so  that  there  is  no  demarcation  between  lung  and  pleura.  The 
thickening  of  the  lung  is  greatest  at  the  free  surface,  and  this  is 
usually  the  case  in  disease  of  such  nature.  The  thickened  free  edge 
of  the  lung  contains  many  new  blood-vessels  distended  with  blood- 
corpuscles,  as  may  easily  be  seen  if  the  section  is  examined  under 
sufficient  amplification.  Most  of  these  blood-vessels  are  like  capillaries. 
There  is,  however,  one  blood-vessel  near  the  free  edge  of  the  lung 
(Fig.  2 1)  which  is  of  quite  different  appearance.  It  is  thick  walled  and 
has  a  very  small  opening,  which  is  placed  to  one  side,  instead  of  in  the 
centre  as  the  calibres  of  normal  vessels  always  are.  The  calibre  is 
lined  with  a  single-coated  layer  of  endothelium  which  contains  endo- 
thelial  cells  and  this  layer  looks  like  a  string  of  beads.  The  ring  of 
endothelium  with  its  cells  is  exactly  like  the  primitive  aorta  of  the 
chick  embryo,  pictures  of  which  are  included  in  almost  all  the  text- 
books of  embryology.  Greater  amplification  than  was  used  in  making 
the  drawing  (Fig.  21)  is  necessary  to  reveal  all  the  details  of  structure 
of  the  minute  blood-vessel,  but  the  general  characteristics  are  pretty 
well  shown.  The  tissue  somewhat  resembles  that  shown  by  Fig.  20, 
and  is  quite  unlike  any  ordinary  normal  human  tissue,  but  is  in  many 
respects  like  that  of  embryos.  There  can  be  no  question  that  this 
curious  irregularly  rounded  collection  of  atypical  cells  with  its  opening 
out  of  centre  is  a  blood-vessel,  but,  on  the  other  hand,  it  is  impossible  to 
be  certain  whether  it  is  one  of  the  normal  vessels  which  was  changed  by 
disease  or  if  it  is  a  new  blood-vessel  which  has  developed  in  the  lung 
tissue  owing  to  the  hyperplasia.  I  believe  it  to  be  a  new  growth  and 
that  such  abortive  blood-vessels  are  common  in  various  hyperplasias. 
The  opinion  of  Ziegler,  which  it  has  been  said  is  representative  of  the 
views  of  pathologists,  has  been  quoted  that  "  the  formation  of  new 
blood-vessels  plays  a  chief  part  in  hyperplasias  of  every  kind.  Wher- 
ever fibrous  tissue,  bone-tissue,  gland-tissue,  or  any  other  is  produced 
in  quantity,  new  blood-vessels  must  of  necessity  be  developed." 

One  of  the  most  extraordinary  things  in  connection  with  this  growth 
of  new  vessels  in  disease  is  the  manner  in  which  nature  seems  frequently 
to  fail  to  attain  the  object  she  set  out  to  accomplish.  Owing  appar- 
ently to  irregular  and  exuberant  growth  of  the  cells,  useless  solid 
cords  are  produced1  instead  of  tubes  capable  of  performing  their 

1  Origin  of  Disease,  by  Arthur  V.  Meigs,  2d  edition,  page  50  and  Fig.  15  :  J.  B.  Lippincott 
Co.,  Philadelphia,  1890. 


3o  HUMAN  BLOOD-VESSELS 

natural  function  of  carrying  blood,  or  other  irregular  and  apparently 
useless  formations  grow,  which  can  be  explained  only  as  abortive  at- 
tempts to  form  blood-vessels,  without  which  no  tissue  can  attain  any 
considerable  size  and  continue  to  exist.  The  drawing  Fig.  15,  in  "  The 
Origin  of  Disease,"  is  a  perfect  type  of  this  kind  of  abortive  for- 
mation. In  the  embryo,  tubes  are  formed,  as,  for  instance,  the 
Miillerian  duct  in  a  part  of  its  length,  as  solid  cords  of  cells  in  which 
the  opening  is  afterwards  channelled  out ;  but  this  does  not  occur, 
as  far  as  is  known,  in  the  case  of  blood-vessels.  The  appearance  of 
many  of  these  abortive  new  blood-vessels  is  such  as  to  forbid  the  be- 
lief that  they  had  at  any  time  large  calibres  and  thin  walls,  as  is 
natural.  It  is  much  more  probable  they  were  deformed  from  their 
very  origin,  and  were  the  result  of  the  innate  tendency  the  organism 
has  to  produce  blood-vessels  in  any  formation  as  soon  as  it  attains 
sufficient  size  to  make  them  necessary  to  its  continued  existence. 

Fig.  22  shows  a  section  from  the  free  edge  of  the  lung  of  a  negro 
man  twenty-four  years  old  who  died  of  phthisis  pulmonalis.  It  in- 
cludes the  pleura,  which  is  greatly  thickened  and  contains  a  good 
many  new  blood-vessels  and  a  portion  of  lung  tissue.  The  normal 
pleura  is  very  thin,  is  almost  avascular,  is  composed  of  many  threads 
of  fibrous  tissue,  contains  but  few  nuclei,  and  there  are  generally  but 
few  cells  distinguishable  in  it.  This  thickened  pleura  is  a  fibrocellu- 
lar  tissue  rich  in  cells.  The  new  blood-vessels  are  filled  with  red  cor- 
puscles and  their  walls  are  formed  of  endothelium,  like  capillaries, 
but,  as  the  vessels  are  much  larger  than  ordinary  capillaries,  the  walls 
are  thicker  ;  there  is,  however,  no  division  into  three  coats.  The  two 
blood-vessels  which  are  shown  in  the  lung-tissue  are  probably  of  the 
same  nature  as  those  in  the  pleura.  The  lung-tissue  itself  is  denser 
than  normal,  owing  to  the  inflammatory  hyperplasia.  These  new 
blood-vessels  are  of  the  same  type  as  most  of  those  shown  by  Fig. 
21,  and  are  typical  of  the  ordinary  new  blood-vessels  of  hyperplasias. 
It  is  quite  common  to  find  the  pleura  thickened  in  various  kinds 
of  acute  and  chronic  disease,  and  very  often  there  are  hardly  any 
blood-vessels  in  the  thickened  diseased  tissue.  The  fact  that  the 
envelopes  of  the  thoracic  and  abdominal  viscera  and  the  portions  of 
these  organs  near  the  surface  are  more  often  diseased  than  their  deeper 
portions  is  a  very  curious  one,  and  one  that  has  as  yet  received  no 
explanation. 


FIG.  21. — NEW  BLOOD-VESSELS  IN  LUNG  AND  IN  PLEURA.     (X  50.) 

From  a  negro  man  forty-nine  years  old  who  died  of  Bright's  disease,  dis  directly  above 
a  cross-section  of  a  thick-walled  blood-vessel,  of  which  the  opening  is  not  centrally  placed, 
and  which  is  lined  by  a  thin  layer  of  endothelium  containing  rounded  nuclei  which  look  like 
beads.  The  free  edge  of  the  lung  is  thickened,  being  composed  of  fibrocellular  tissue,  and 
the  pleura  is  bound  to  the  lung,  so  that  no  distinction  between  pleura  and  lung  can  be  seen. 
In  this  tissue  there  are  many  blood-vessels  which  are  cut  in  various  directions,  and  which 
contain  red  blood- corpuscles.  Most  of  these  are  new  blood-vessels. 

FIG.  22. — NEW  BLOOD-VESSELS  IN  THICKENED  PLEURA  AND  IN  LUNG.     (X  50.) 

From  a  negro  man  twenty-four  years  old"  who  died  of  acute  phthisis  pulmonalis.  d  is 
the  free  edge  of  the  pleura  and  e  marks  the  line  of  junction  of  the  thickened  pleura  and  the 
lung.  In  the  thickened  pleura  there  are  numerous  blood-vessels  which  contain  red  blood- 
corpuscles,  and  in  the  lung-tissue  there  are  similar  vessels.  All  of  these  vessels  have  walls 
of  fibrous  tissue  like  very  large  capillaries,  none  of  them  being  provided  with  three  coats 
as  arteries  and  veins  are.  The  blood-vessels  are  a  new  growth  resulting  from  disease. 


FIG.  22. 


d 


9E 


NEW  BLOOD-VESSELS  31 

Fig.  23  depicts  a  portion  of  the  thickened  pleura  and  diseased 
lung  of  a  negro  woman  seventy  years  old  who  died  of  Bright's  disease. 
The  pleura  is  many  times  the  normal  thickness,  and  the  lung-tissue, 
instead  of  being  of  open  texture  like  normal  lung,  is  composed  of  a 
dense  fibrocellular  tissue  containing  pigment.  The  purpose  of  the 
drawing,  however,  is  to  show  the  new  blood-vessels.  There  are  several 
in  the  dense  lung-tissue  near  the  pleura  and  one  which  extends  from 
the  lung-tissue  into  the  thickened  pleura.  In  the  normal  state  there 
are  few  if  any  blood-vessels  extending  into  the  pleura  from  the  lung, 
certainly  none  of  such  great  size  as  this  one.  The  existence  of  this 
vessel  is  another  exemplification  of  how  nature  provides  a  new  blood 
supply  whenever  there  is  any  hyperplasia  like  this  thickening  of  the 
pleura. 

Figs.  21,  22,  and  23  demonstrate  a  peculiarity  of  disease  which  I 
have  elsewhere  discussed  at  considerable  length,1  but  to  which  allusion 
may  now  be  made.  Fig.  2 1  depicts  lung-tissue  from  a  man  of  forty- 
nine,  and  Fig.  23  from  a  woman  of  seventy,  and  both  died  of  Bright's 
disease.  Fig.  22  shows  pulmonary  tissue  from  a  man  twenty- four 
years  old  who  died  of  phthisis  pulmonalis.  Of  the  two  who  died  of 
Bright's  disease  one  was  past  middle  life  and  the  other  was  old,  but 
the  man  who  died  of  phthisis  was  still  young.  Although  the  ages 
were  so  different  and  the  diseases  so  unrelated,  there  is  a  general  simi- 
larity of  the  effects  produced  upon  the  tissue.  Morbid  fibroid  tissue 
grew  in  the  lung,  and  fibroid  tissue  of  that  character  contains  a  greater 
or  a  less  number  of  demonstrable  cells,  according  to  the  rate  of 
growth.  In  disease  which  has  proceeded  rapidly  there  are  many 
cells  in  the  diseased  tissue,  and  in  chronic  disease  dense  fibrous  tissue 
is  produced  which  contains  but  few  cells.  This  morbid  fibrosis,  or 
disease  of  age  as  I  have  elsewhere  described  it,  is  inevitable  in  human 
beings  as  they  grow  older,  and  is  often  produced  in  the  young  by 
disease  when  they  fall  into  the  condition  of  premature  age. 

The  most  dissimilar  diseases  produce  the  same  change  of  the  tis- 
sues, and  it  is  very  nearly  correct  to  say  that  every  kind  of  disease 
tends  to  cause  the  production  of  morbid  fibroid  tissue.  A  curious 
clinical  fact  is  that  the  appearance  of  symptoms  denoting  the  presence 
of  disease  in  man  has  been  preceded,  for  a  long  time  perhaps,  by  the 


1  The  Origin  of  Disease,  Chapter  II. 


32  HUMAN  BLOOD-VESSELS 

latent  growth  of  morbid  fibroid  tissue  in  the  body.  Fig.  24  shows 
the  spleen  of  a  negro  woman  of  seventy  years  who  died  of  Bright's 
disease,  the  same  patient  from  whom  Fig.  23  was  obtained,  and, 
therefore,  it  might  well  be  expected  that  there  would  be  morbid  fibroid 
tissue  present,  as  morbid  fibrosis  is  a  disease  which  is  apt  to  be  wide- 
spread in  the  tissues  of  those  who  have  it,  especially  in  the  aged. 
The  splenic  tissue  does  not  appear  to  be  abnormal;  the  capsule, 
however,  is  exceedingly  thick  and  is  composed  of  at  least  three  layers 
of  different  tissues.  As  these  are  shown  by  the  drawing,  the  old 
normal  capsule  is  below,  and  next  above  it  is  new  material  the  result 
of  hyperplastic  growth.  Above  this  is  still  another  tissue  which  is 
rich  in  cells  and  which  contains  a  number  of  good-sized  new  blood- 
vessels. There  are  some  small  new  blood-vessels  in  the  middle 
layer  of  the  capsule  also.  The  uppermost  layer  of  the  capsule  was 
evidently  of  rather  recent  growth,  for  old  tissues  are  usually  more 
densely  fibrous  and  less  rich  in  cells,  and  it  probably  constituted  a 
portion  of  an  adhesion  by  which  the  spleen  was  fixed  to  some  adjacent 
structure,  for  in  this  case  the  abdominal  viscera  were  almost  all  ad- 
herent to  one  another  and  to  the  surrounding  parts.  Such  adhesions 
are  very  common  in  cases  of  chronic  maladies,  and  especially  in  Bright's 
disease.  When  the  capsule  of  the  spleen  is  diseased  as  the  result 
of  a  chronic  process,  it  is  prone  to  become  thick  and  dense,  some- 
times of  a  texture  almost  like  horn,  and  contains  but  few  blood-vessels, 
but  when  the  disease  has  been  of  rapid  progress  there  are  many  new 
vessels.  The  appearance  shown  by  Fig.  24  is  very  common  in  chronic 
disorders  and  in  aged  persons,  and  the  production  of  new  blood- 
vessels is  an  invariable  part  of  the  change. 

In  the  lung,  in  cases  of  tuberculosis,  it  is  quite  common  to  find 
certain  curious  formations  which  have  been  named  giant  cells.  Giant 
cells  are  also  frequently  found  in  the  liver,  spleen,  and  kidney  and  in 
other  tissues.  At  one  time  they  were  thought  to  be  peculiar  to  tuber- 
culosis, and  their  discovery  in  any  tissue  was  considered  a  certain 
indication  of  the  existence  of  tubercular  disease.  It  has  been  proved, 
however,  that  they  exist  in  non-tubercular  tissue.  They  develop,  for 
instance,  in  granulation  tissue.  It  is  difficult  to  comprehend  how  they 
came  to  be  called  giant  cells.  Evidently  in  their  full  state  of  develop- 
ment they  are  not  cells  at  all,  but  are  complex  formations  composed 
of  many  cells.  The  general  structure  of  giant  cells  and  of  the  cells 


FIG.  23. — NEW  BLOOD-VESSELS  OF  THE  LUNG.     (X  50.) 

From  a  negro  woman  seventy  years  old  who  died  of  Bright's  disease,  d  is  the  free  sur- 
face of  the  pleura  and  e  the  line  of  junction  of  the  pleura  and  lung.  The  pleura  is  composed 
of  coarse  fibrous  tissue  and  is  greatly  thickened.  There  is  a  new  blood-vessel  passing  from 
the  lung  into  the  thickened  pleura.  The  vessel,  although  of  good  size,  has  a  wall  composed 
of  tissue  like  that  of  ordinary  capillaries,  but  thicker  than  that  of  the  smaller  capillaries. 
There  is  no  muscular  tissue  in  it.  There  are  a  number  of  other  blood-vessels  in  the  lung- 
tissue  which  are  filled  with  blood-corpuscles.  These  do  not  look  like  the  normal  blood- 
vessels of  the  lung. 

FIG.  24. — NEW  BLOOD-VESSELS  IN  NEW  TISSUE.      (X  105.) 

A  section  of  spleen,  including  the  capsule  and  superimposed  new  tissue,  from  a  negro 
woman  seventy  years  old  who  died  of  Bright's  disease,  h,  splenic  pulp  ;  f,  true  capsule  ; 
g;  morbid  tissue  superimposed  upon  the  capsule  ;  »,  the  uppermost  layer  of  the  new  tissue. 
It  contains  the  new  blood-vessels  and  many  cells  such  as  are  commonly  found  in  new  and 
rapidly  growing  tissues.  The  vessel  walls  are  formed  of  simple  fibrous  tissue,  there  being 
no  differentiation  into  three  coats  and  no  muscular  tissue.  New  blood-vessels  are  generally 
of  this  character.  The  tissue  in  which  these  vessels  lie  is  probably  a  portion  of  one  of  the 
adhesions  by  which  the  spleen  was  fixed  to  adjacent  parts. 


FIG.  23. 


FIG.  24. 


:    --S -••-  , 


c 


•— rjv;  -..->    '••' 
XC-v'W^..     ... 


y/  o    )77  m 


NEW  BLOOD-VESSELS  33 

of  which  they  are  formed  can  easily  be  seen  and  studied  with  the 
microscope.  The  size  of  a  well-formed  giant  cell  is  so  great  as  at  once 
to  show  the  impropriety  of  calling  it  a  cell.  No  cell  of  the  human 
organism  has  ever  been  known  to  attain  to  anything  like  the  size  of  a 
large  giant  cell.  In  view  of  the  inherent  tendency  of  nature  to  produce 
new  blood-vessels  in  all  hyperplasias,  it  is  only  reasonable  to  think  they 
sometimes  grow  in  tubercles,  and  I  believe  that  giant  cells  are  the  re- 
sult of  nature's  effort  to  form  new  blood-vessels.  Some  authorities 
have  suggested  that  giant  cells  in  tubercles  are  blood-vessels  whose 
calibres  have  been  obliterated  by  the  disease.  I  think  it  is  more  likely 
they  are  caused  by  abortive  attempts  to  produce  new  blood-vessels 
than  that  they  are  old  vessels  which  were  destroyed.  A  comparison 
of  various  forms  of  giant  cells  with  new  blood-vessels  shows  that  in 
many  respects  they  resemble  each  other. 

Figs.  15  and  21,  from  "The  Origin  of  Disease,"  depict  deformed  or 
aborted  new  blood-vessels.  Many  of  the  cells  that  compose  these  vessels 
are  like  epithelium  and  they  bearlittle  resemblance  to  the  cells  of  normal 
blood-vessels.  In  two  of  the  three  vessels  the  opening  is  very  small 
and  is  not  central,  and  in  the  third  there  is  no  calibre,  the  aborted 
vessel  being  a  solid  cylinder.  These  illustrations  seem  to  me  to  prove 
that  the  start  to  produce  new  blood-vessels  in  diseased  tissues  is 
sometimes  made  and  fails,  the  cells  growing  exuberantly  and  irregu- 
larly, and  that  solid  cylinders  or  odd-shaped  forms  are  produced  that 
are  quite  useless.  Giant  cells  present  many  points  of  resemblance  to 
these  aborted  new  blood-vessels,  as  will  presently  be  shown. 

Authorities  seem  to  agree  that  tubercles  are  non-vascular  and  that 
owing  to  this  peculiarity  they  always  break  down  as  soon  as  they 
attain  great  size.  The  opinion  of  Ziegler  has  already  been  quoted, 
that  "the  formation  of  new  blood-vessels  plays  a  chief  part  in  hyper- 
plasias of  every  kind."  Pathological  studies  show  that  when  any  new 
growth  arises  there  is  a  strong  tendency  on  the  part  of  nature  at  once 
to  provide  a  supply  of  blood,  and  tubercular  disease  certainly  often 
partakes  of  the  nature  of  a  hyperplasia,  for  tuberculous  lungs  fre- 
quently are  much  larger  and  heavier  than  normal.  If  such  be  nature's 
law  it  would  be  strange  if  the  only  exception  to  it  were  in  the  case  of 
tubercles.  The  statement  that  tubercles  are  completely  non-vascular 
is  not  literally  true.  Probably  what  is  meant  by  those  who  say  that 
tubercles  are  non-vascular  is  that  new  blood-vessels  do  not  develop  in 
3 


34  HMttff  BLOOD-VESSELS 


them  ;  but  no  one  woul^assert  that  the  blood-vessels  in  a  tissue 
which  is  invaded  by  tubezular  disease  do  not  continue  to  exist  for  a 
time  after  the  disease  h^»egun.  It  must  be,  therefore,  that  tubercles 
are  supplied  with  bloodgfluring  their  earlier  stages,  until  there  has 
•been  time  to  shut  off  the-«1iormal  vessels.  I  have  a  number  of  speci- 
mens of  tubercular  disefese  of  the  lung  of  which  the  vessels  were 

. 
injected,  and  they  show  i-A  the  most  satisfactory  manner  that  there 

are  many  blood-vessels  in  the  tubercles.  In  lung  tubercles  which  are 
uninjected  it  is  also  easy  to  recognize  blood-vessels  within  the  tu- 
bercles. Such  blood-vessels,  however,  commonly  give  the  impres- 
sion that  they  were  in  process  of  extinction,  owing  to  the  cellular 
infiltration  and  increasing  density  of  the  tissue,  rather  than  that  they  are 
new  or  are  developing. 

The  tubercular  process  in  the  human  lung  is  subject  to  wide  varia- 
tion. Sometimes  it  is  rapid,  and  in  other  cases  very  slow  in  its 
progress,  lasting  even  for  years.  In  rapid  pulmonary  tuberculosis  the 
effect  produced  is  exactly  similar  to  what  happens  in  cases  of  miliary 
abscess,  so  that  often  even  a  skilled  observer  cannot  from  a  micro- 
scopical examination  alone  distinguish  the  one  disease  from  the  other  at 
their  beginning,  although  in  their  full  states  of  development  they  are 
so  far  apart  that  it  is  then  difficult  to  believe  there  was  ever  any  resem- 
blance between  them.  In  rapid  tuberculosis  the  cellular  infiltration 
is  overwhelming  and  the  process  is  destructive  from  the  first.  The 
blood-vessels  in  the  invaded  tissue  are  soon  cut  off  and  destroyed. 
There  is  every  reason  to  believe  that  in  this  form  of  tuberculosis  there 
is  not  time  for  the  formation  of  new  blood-vessels.  In  disease  of  this 
nature  few  or  no  giant  cells  are  found.  When  pulmonary  tubercu- 
losis has  progressed  more  slowly,  the  effect  is  very  different.  Besides 
the  infiltration  with  round  cells  a  great  quantity  of  fibrous  tissue  is 
produced  which  is  well  organized  and  is  supplied  with  blood-vessels. 
It  is  in  this  tubercular  tissue  of  slower  growth  that  giant  cells  are 
generally  found  to  be  numerous  and  well  developed.  Such  giant  cells 
often  present  peculiarities  of  form  and  character  which  suggest  that 
they  are  aborted  blood-vessels.  If  giant  cells  are,-  as  I  believe,  aborted 
new  blood-vessels,  the  fact  constitutes  proof  that  new  blood-vessels 
grow  in  the  tissues  of  adults  independently  of  the  general  vascular 
system,  as  they  are  known  to  grow  in  embryos,  as  I  have  already  in 
this  chapter  tried  to  show.  The  prevalent  disbelief  in  the  indepen- 


NEW  BLOOD-VESSELS  35 

dent  growth  of  new  blood-vessels  in  diseased  tissues  and  the  opinion 
that  they  are  always  offshoots  from  pre-existing  vessels  stand  in  the 
way  of  the  acceptance  of  the  theory  that  giant  cells  are  aborted 
blood-vessels. 

Fig.  25  shows  a  number  of  giant  cells  from  the  lung,  liver,  and. 
spleen.  Some  of  them  are  from  a  man  sixty  years  old  who  died  of 
phthisis,  and  the  others  are  from  a  woman  twenty- five  years  old  who 
died  of  meningitis  and  pulmonary  tuberculosis.  The  description  of 
the  plate  giver;  the  details  in  regard  to  each  one  of  the  giant  cells. 
These  assume  a  great  variety  of  forms  and  their  appearance  indicates 
that  they  are  disposed  to  be  irregularly  cylindrical  or  oblong.  Al- 
most all  of  them  have  a  fringe  of  cells  forming  an  outer  layer,  while 
their  central  portions  consist  of  a  structureless,  grumous-looking 
material.  According  to  their  relation  to  the  plane  of  section 
they  appear  as  circular,  irregularly  elliptical,  or  oblong.  The  fringe 
of  cells  forming  the  outer  layer  of  most  giant  cells  is  incomplete 
(g,  i,j,  and  /),  but  sometimes  the  cells  are  disposed  in  a  complete  circle 
(c,  /£).  In  one  figure  (/£)  there  are  two  giant  cells  which  are  attached, 
by  prolongations  of  the  cells  which  form  the  external  rings,  to  a  blood- 
vessel which  is  close  to  them.  The  vessel  is  full  of  blood-corpuscles, 
and  the  intimate  attachment  to  it  of  the  giant  cells  suggests  that  they 
had  some  relation  to  the  vascular  system.  The  appearances  of  some 
of  the  giant  cells  (a,  d,  e,f,  and  ;;/)  strongly  suggest  that  they  are  due  to 
nature's  abortive  efforts  to  produce  new  blood-vessels  in  hyperplastic 
tissue.  They  appear  to  be  solid  cylinders  which  were  cut  in  various 
directions.  Some  of  them  (a,  e,  /)  suggest  very  strongly  by  their 
appearance  that  they  are  partially  hollow  cylinders,  or  that  they  were 
in  process  of  becoming  tubular.  This  effect  has  been  very  faithfully 
represented  by  the  artist,  and  it  is  not  exaggerated  in  the  drawings. 

The  formation  of  giant  cells  in  tubercles  is  a  very  common  feature 
of  tuberculosis,  and  there  must  be  some  explanation  for  the  constant, 
growth  of  these  peculiar  bodies.  To  call  them  giant  cells  is  a  mis- 
nomer, for  evidently  they  are  not  cells  but  are  complex  bodies  formed 
of  cells.  If  they  are  not  cells,  what  are  they?  Blood-vessels  exist 
everywhere  in  the  soft  tissues,  and  blood-vessels  grow  in  all  hyper- 
plasias  unless  tubercles  form  the  single  exception  to  an  otherwise  uni- 
versal rule.  Although  it  is  impossible  from  existing  evidence  to  prove 
that  giant  cells  are  deformed  or  abortive  new  blood-vessels,  I  believe 


36  HUMAN  BLOOD-VESSELS 

it  is   much  more  reasonable  to  accept  such  an  explanation  of  their 
occurrence  as  a  working  hypothesis  than  to  call  them  cells. 

All  of  the  foregoing  discussion  of  new  blood-vessels  is,  I  am 
aware,  imperfect,  but  the  whole  subject  is  at  present  in  an  unsatisfac- 
tory state  and  the  information  in  regard  to  it  that  can  be  found  in 
medical  literature  is  very  incomplete. 


FIG.  25. — GIANT-CELLS.     (X  260. ) 

a  shows  liver  of  a  man  sixty  years  old  who  died  of  phthisis.  The  giant-cell  is  cylindri- 
cal and  was  cut  across  at  its  upper  end.  It  looks  like  a  tube,  b  is  lung  from  the  same 
case  as  a.  The  giant-cell  is  nearly  circular,  has  an  almost  complete  outer  fringe  of  cells,  and 
is  surrounded  by  an  empty  space,  except  at  .the  upper  left-hand  portion,  where  a  peduncle 
attaches  the  giant-cell  to  the  lung-tissue,  c  is  lung  from  the  same  case  as  a.  The  giant- 
cell  is  nearly  round,  except  for  an  irregular  projection  to  the  left.  Its  outer  border  of  cells 
is  complete  and  the  centre  is  composed  of  material  without  definite  structure.  It  is  sur- 
rounded by  a  space,  d  is  liver  from  the  same  case  as  a.  The  giant  cell  looks  like  a  cylin- 
der that  had  been  cut  obliquely  across,  and  the  appearance  suggests  that  it  may  have  been  a 
tube,  e  is  liver  from  the  same  case  as  a.  The  giant-cell  is  partly  separated  from  the  sur- 
rounding tissue  by  a  space.  The  arrangement  of  the  cells  at  its  sides  and  above  makes  it  look 
as  if  obliquely  cut,  and  as  if  it  were  hollow  or  partly  hollow,  f  is  liver  from  the  same  case 
as  a.  The  giant-cell  consists  of  an  obliquely  cut  ring  of  cells  with  a  projection  below.  It 
is  like  a  cylinder  or  a  tube,  g  is  liver  from  the  same  case  as  a.  The  outer  ring  of  cells  is 
incomplete,  which  is  a  very  common  feature  of  giant-cells,  h  is  liver  from  the  same  case  as 
a.  There  are  two  giant-cells  above  which  consist  of  incomplete  rings  of  cells  of  irregular 
shape.  Below  these  is  fibrocellular  lung-tissue,  and  at  the  lower  part  of  the  drawing  is  a 
giant-cell  which  is  irregularly  cylindrical,  and  has  at  its  upper  portion  an  irregular  and  al- 
most shadowy  ring  of  cells.  This  looks  like  an  obliquely  cut  tube  or  cylinder,  i  is  spleen 
of  a  woman  twenty-five  years  old  who  died  of  meningitis  and  pulmonary  tuberculosis.  The 
giant-cell  is  formed  of  an  incomplete  ring  of  cells  with  structureless  material  in  the  centre. 
j  is  lung  from  the  same  case  as  i,  to  which  it  is  very  similar  but  smaller,  k  is  lung  from 
the  same  case  as  i.  There  are  three  giant-cells,  one  above  and  two  below,  and  there  is  a 
small  blood-vessel,  containing  corpuscles,  in  the  middle.  The  giant-cell  above  is  a  common 
type.  The  two  below  appear  to  have  been  cut  obliquely,  and  from  the  outer  fringe  of  cells 
there  is  an  extension  attaching  each  of  them  to  the  adjacent  blood-vessel.  /  is  lung  from 
the  same  case  as  i.  This  giant-cell  is  very  like  i  and  j,  and  is  midway  between  them  in 
size.  In  all  of  the  three  the  encircling  ring  of  cells  is  incomplete,  m  is  spleen  from  the 
same  case  as  a.  There  are  two  giant-celis  which  are  of  irregular  shape.  A  study  of  all  of 
the  giant-cells  makes  it  obvious  that  they  are  miscalled  cells,  and  that  they  are  complex  for- 
mations of  considerable  size.  They  were  all  accurately  drawn  to  scale. 


CHAPTER     IV 
DISEASE  OF  BLOOD-VESSELS  IN  GENERAL 

IT  is  more  satisfactory  to  study  disease  of  the  blood-vessels  than 
disease  of  the  large  organs,  for  the  largest  blood-vessels  are  small  in 
comparison  with  the  great  organs  ;  and,  as  no  study  of  disease  is  com- 
plete without  microscopical  examination,  which  can  be  made  only  with 
small  masses  of  tissue,  the  reason  why  the  study  of  blood-vessels  is 
satisfactory  is  obvious.  Complete  cross-sections  of  the  largest  human 
blood-vessels  can  easily  be  prepared  for  examination  with  the  highest 
powers  of  the  microscope,  and  the  study  of  a  section  across  a 
blood-vessel  is  in  a  certain  sense  complete.  If  large  organs  like  the 
brain  or  liver  or  even  the  kidney  are  to  be  examined  microscopically 
for  disease,  it  is  feasible  to  select  only  such  portions  as  can  be  seen 
with  the  naked  eye  to  be  diseased,  and  then  to  pick  out  haphazard 
other  portions.  It  is  impracticable  to  make  a  microscopical  examina- 
tion of  the  whole  of  one  of  the  large  organs,  and,  as  disease  sufficient 
to  impair  the  usefulness  of  an  organ  is  often  quite  invisible  to  the 
unaided  eye,  it  must  frequently  happen  that  a  grave  malady  escapes 
detection. 

There  is  less  known  of  disease  of  the  capillaries  than  of  disorders 
either  of  the  arteries  or  of  the  veins,  and  the  pathology  of  the 
veins  has  been  less  extensively  studied  than  that  of  the  arteries. 
This  is  true  notwithstanding  the  fact  that  many  of  the  veins  lie  upon 
the  surface  of  the  body  so  that  the  morbid  changes  they  undergo  are 
readily  perceived.  Varicose  veins,  for  instance,  are  very  common, 
and  the  condition  has  long  been  known  and  causes  a  great  deal  of  suf- 
fering and  disability,  but  its  causes  are  little  understood.  Not  much 
has  yet  been  learned  of  the  physical  changes  that  occur  in  the  veins 
themselves  owing  to  disease.  On  the  other  hand,  the  objective  study 
of  the  pathology  of  the  arteries  has  been  pursued  to  great  length  and 
a  large  store  of  facts  has  been  accumulated.  Although  many  of  the 
morbid  changes  in  the  walls  of  arteries  are  well  known,  there  is  as  yet 
no  satisfactory  understanding  of  the  ulterior  results  of  these  alterations 
if  the  arteries  themselves  continue  patulous  and  are  thus  able  still  to 
accomplish  their  most  important  function  of  carrying  blood.  It  has 

37 


38  HUMAN  BLOOD-VESSELS 

been  neccessary  to  abandon  many  opinions  formerly  prevalent  in 
regard  to  arterial  disease.  For  example,  endarteritis  was  at  one  time 
supposed  to  be  due  in  most  instances  to  syphilis,  and  it  was  thought 
to  be  possible  from  a  microscopical  examination  alone  to  determine 
whether  a  lesion  was  of  syphilitic  origin.  It  is,  however,  now  well 
known  that  endarteritis  is  one  of  the  commonest  vascular  changes  that 
take  place  in  elderly  people,  that  it  is  due  to  other  causes  much  more 
frequently  than  to  syphilis,  and  that  it  is  impossible  to  ascertain  from 
the  appearances  alone  whether  in  a  particular  case  of  endarteritis  the 
lesion  is  syphilitic. 

Very  little  is  yet  known  of  the  effects  of  changes  of  the  anatomical 
constitution  of  the  walls  of  the  arteries  and  veins,  although  much  care 
has  been  bestowed  upon  the  study  of  the  different  coats  of  the  ar- 
teries and  elaborate  theories  have  been  evolved  regarding  diseases  of 
the  intima,  the  muscularis,  and  the  adventitia,  and  as  to  perivascular 
disease.  Increased  experience  has  convinced  me  that  pathological 
changes  in  the  perivascular  tissue  and  the  adventitia  of  the  arteries 
and  veins  are  much  more  common  than  I  formerly  believed.  It  is 
always  difficult  in  dealing  with  this  subject  to  separate  in  a  satisfactory 
manner  perivascular  disease  from  disease  of  the  fibrous  coat  of  arteries 
and  veins.  The  distinction  is  of  importance,  for  upon  it  turns  the 
decision  of  the  question  whether  in  a  particular  case  the  malady  is 
of  vascular  origin  or  arose  outside  in  the  connective  tissue.  It  is 
possible  for  disease  to  begin  in  blood-vessels  and  then  by  extension 
to  involve  surrounding  parts,  or  it  may  have  its  origin  outside  the 
blood-vessels  and  later  include  them  by  extension  as  it  spreads  itself 
over  a  larger  area. 

On  some  accounts  anatomical  and  pathological  classifications  would 
be  more  satisfactory,  and  I  believe  more  truly  descriptive  of  nature,  if 
arteries  and  veins  were  said  to  have  only  two  coats — the  muscularis 
and  the  intima — and  the  fibrous  coat  were  classified  as  belonging  to 
the  perivascular  connective  tissue.  It  is  always  impossible  to  decide 
just  how  much  of  the  fibrous  tissue  surrounding  it  belongs  to  an 
artery  or  to  a  vein  and  how  much  is  perivascular  connective  tissue. 
If  a  large  artery  or  vein  be  dissected  from  the  tissue  in  which  it  lies, 
there  is  always  a  question  how  much  fibrous  tissue  should  be  brought 
away  as  belonging  to  the  adventitia  of  the  vessel.  In  the  same  way, 
if  arteries  or  veins  are  examined  with  the  microscope  in  sections  which 


DISEASE  OF  BLOOD-VESSELS  IN  GENERAL  39 

have  been  cut  without  disturbing  the  relations  of  the  vessels  and  the 
surrounding  tissue,  a  distinction  cannot  be  made  between  the  fibrous 
coat  of  the  vessel  and  the  fibrous  tissue  in  which  it  lies.  There  is  no 
line  of  demarcation  between  them,  for  the  one  shades  imperceptibly 
into  the  other.  All  classifications  are  artificial,  for  they  all  draw  hard 
lines  and  nature  draws  none.  The  more  I  have  studied  the  subject 
of  classification  the  more  I  am  convinced  that  arteries  and  veins 
should  be  considered  to  have  but  two  coats,  muscularis  and  intima, 
as  stated  above.  Gull  and  Sutton,  in  their  description  of  arterio- 
capillary  fibrosis  which  has  become  one  of  the  classics  of  medicine, 
were  the  first  to  make  known  the  important  role  which  is  played  by 
the  blood-vessels  in  most  of  the  chronic  diseases.  It  is  impossible, 
however,  even  after  the  lapse  of  so  many  years,  to  be  certain  whether 
the  disease  which  was  the  basis  from  which  their  conclusions  were 
drawn — namely,  fibrosis  of  the  kidney — is  truly  of  vascular  origin  or 
begins  in  some  other  portion  of  the  renal  tissue  and  secondarily  pro- 
duces its  effects  upon  the  blood-vessels. 

The  muscular  coat  of  arteries  is  often  greatly  thickened  and  this 
thickening  has  been  called  hypertrophy,  and  the  disease  has  been 
made  the  foundation  for  elaborate  theories,  it  being  said  that  the 
walls  of  the  thickened  vessels  acquire  a  great  increase  of  strength,  and 
by  their  power  of  contraction  check  the  circulation,  reducing  the 
amount  of  blood  supplied  to  parts  to  which  it  flows  through  such 
arteries.  The  function  of  the  muscular  coat  of  the  arteries  and  veins 
is  not  so  well  understood  as  it  is  to  be  hoped  that  it  some  day  will 
be.  Whether  the  contractility  with  which  the  muscularis  is  endowed 
has  only  to  do  with  regulating  the  intravascular  pressure,  or  if  it  fur- 
nishes part  of  the  force  which  drives  the  blood  onward,  or  if  its  func- 
tion is  something  which  has  as  yet  entirely  eluded  observation,  is  a 
question  for  the  physiology  of  the  future  to  answer.  This  statement 
may  be  thought  to  be  rash,  but  it  certainly  is  true  that  the  function  of 
the  muscular  coat  is  not  known  in  the  same  way  that  it  is  known  that 
the  contraction  of  the  heart  muscle  drives  the  blood  through  the 
vessels.  My  own  studies  of  the  muscularis  of  arteries  and  veins  have 
not  yet  led  me  to  the  discovery  of  a  law  governing  the  relative  fre- 
quency of  disease  of  it  and  of  the  other  two  coats,  but  I  believe  the 
intima  to  be  the  most  subject  of  the  three  coats  to  disease,  the  mus- 
cularis to  occupy  the  second  place,  and  that  disease  of  the  adventitia 


40  HUMAN  BLOOD-VESSELS 

is  the  most  rare.  Morbid  thickening  of  the  muscularis  is  very  common 
and  is  easily  recognized.  The  question  what  is  the  nature  of  the 
tissue  seen  when  such  a  thickened  muscularis  is  examined  with  the 
higher  powers  of  the  microscope  is  a  very  different  one,  and  one 
much  more  difficult  to  answer.  There  can  be  no  doubt  that  in  such 
tissue  the  number  of  muscle  cells  is  increased,  and  this  renders  it 
almost  certain  that  the  actual  amount  of  muscular  tissue  is  increased  ; 
but  it  is  my  opinion,  after  having  studied  a  great  many  diseased  arteries 
and  a  large  number  of  diseased  veins,  that  this  statement  tells  only 
half  the  story.  If  the  so-called  hypertrophied  muscular  tissue  be  care- 
fully examined,  it  becomes  evident  that  there  are  in  it  nuclei  of  a  differ- 
ent character  from  the  muscular  nuclei,  and  that  in  many  instances  the 
muscular  nuclei  and  threads  of  muscular  tissue  are  more  widely  sepa- 
rated than  in  the  healthy  involuntary  muscle  of  the  blood-vessels. 
In  some  instances  the  nature  of  the  material  which  separates  the 
muscular  elements  cannot  be  determined,  although  even  in  such  cases 
it  is  evident  that  the  tissue  is  not  wholly  made  up  by  an  increase 
of  the  muscular  tissue,  but  in  others  it  is  possible  to  recognize  with 
certainty  that  connective  tissue  has  grown  among  the  muscle  nuclei 
and  fibres.  As  I  have  studied  this  so-called  hypertrophy  of  the 
muscular  tissue  of  the  blood-vessels,  I  have  been  irresistibly  driven 
to  the  conclusion  that  the  process  is  a  degenerative  one.  Quite  fre- 
quently it  is  possible  to  see,  in  sections  of  arteries  of  which  the  mus- 
cular coat  is  thickened,  that  the  thickened  tissue  is  in  a  condition  of 
fibroid  degeneration,  and  it  is  impossible  to  believe  that  such  tissue 
could  have  endowed  the  artery  with  increased  contractile  power. 
Incidentally  it  may  be  said  that  I  have  reached  a  similar  conclusion 
in  regard  to  hypertrophy  of  the  heart, — that  it  is  a  degenerative 
process,  and  is  not  compensatory  as  it  is  commonly  described  to  be.1 
The  question  what  causes  the  great  increase  of  the  bulk  and 
weight  of  the  human  heart  that  often  occurs  in  disease,  and  in  an 
exactly  analogous  way  of  the  muscular  coat  of  arteries  and  veins,  is  an 
important  one,  and  one  therefore  worthy  of  careful  consideration. 
The  belief  that  this  strange  process,  which  has  been  named  hypertro- 
phy, is  compensatory  and  beneficial,  is,  I  believe,  without  substantial 
foundation  in  fact.  The  theory  has  been  generally  accepted  that 

1  Origin  of  Disease,  page  84. 


DISEASE  OF  BLOOD-VESSELS  IN  GENERAL  41 

hypertrophy  of  the  heart  is  nature's  effort  to  overcome  the  ill  effects 
of  leaking  of  the  valves,  but  the  disease  is  known  in  its  later  stages  to 
be  degenerative  and  to  be  a  cause  of  weakness.  There  is  no  good 
reason  that  I  have  ever  been  able  to  discover  for  the  assertion  that 
hypertrophy  of  the  heart  or  of  the  muscularis  of  arteries  and  veins  is 
compensatory  at  any  stage  of  its  development.  Thickening  of  the 
muscular  coat  of  the  arteries  and  veins  of  any  organ  or  tissue  may 
occur.  For  instance,  although  disease  of  the  intima  is  the  most  com- 
mon lesion  of  the  blood-vessels  of  the  heart  and  kidney,  it  is  quite 
common  to  find  that  the  muscularis  also  is  affected,  and  even  that 
there  may  be  morbid  thickening  of  the  muscularis  of  vessels  that  show 
little  or  no  change  of  the  intima.  The  artery  in  which  I  have  most 
frequently  found  morbid  thickening  of  the  muscular  coat  is  the  radial. 
A  common  disease  of  the  radial  artery  consists  in  a  great  thickening 
of  the  muscularis  while  the  intima  is  but  little  thickened.  The  thick- 
ening of  the  muscularis  is  often  so  great  that  the  disease  is  easily 
recognized  by  even  the  most  casual  examination.  Such  thickening  I 
believe,  as  I  have  already  said,  to  be  due  to  degenerative  growth  and 
changes,  and  not  to  compensatory  hypertrophy  as  has  commonly 
been  thought. 

As  yet  I  have  been  unable  to  discover  the  reason  why  the  radial 
artery  should  be  so  very  liable  to  thickening  of  the  muscularis, 
which  is  a  disease  so  different  from  that  which  is  most  common  in 
the  arteries  of  the  organs  and  especially  of  the  heart  and  kidneys, — 
namely,  thickening  and  degeneration  of  the  intima.  It  may  be  that 
the  blood-vessels  within  the  organs  are  less  subject  to  disease  of 
the  muscularis  than  are  the  arterial  trunks  which  carry  the  blood 
to  the  various  parts  of  the  system.  Such  examinations  of  arteries 
as  I  have  made  seem  to  support  this  view,  for  in  the  femoral, 
popliteal,  brachial,  etc.,  the  muscularis  has  appeared  to  be  proportion- 
ally more  frequently  diseased  than  in  the  arterioles  which  are  within 
such  organs  as  the  heart,  spleen,  and  kidneys.  It  appears  that  the 
blood-vessels  of  the  organs  are  more  liable  to  have  the  intima  first  at- 
tacked by  disease  than  are  the  vessels  which  serve  as  trunks  to  carry 
the  blood  from  part  to  part.  Many  of  the  great  vessels,  both  arteries 
and  veins,  are  but  little  supported  by  surrounding  solid  tissue  in  their 
course  from  the  heart,  which  is  the  centre  of  the  circulation,  to  the 
part  of  the  organism  to  which  they  supply  blood.  The  vascular 


HUMAN  BLOOD-VESSELS 

trunks  of  the  thorax  and  abdomen,  as  well  as  those  of  other  parts  of 
/the  body,  are  like  the  pipes  of  a  system  for  a  water  supply,  which  in 
their  transit  are  hung  in  spaces  without  having  anything  around 
them.  On  the  other  hand,  the  blood-vessels  of  the  organs  are  sur- 
rounded by  tissue  which  is  more  or  less  dense  and  from  which,  in  the 
nature  of  things,  they  must  receive  support.  It  is  not  surprising  that 
blood-vessels  whose  environment  is  so  very  different  should  be 
anatomically  as  different  as  the  great  vascular  trunks  are  from  the 
vessels  within  the  organs,  nor  would  it  be  surprising  if  the  event 
should  show  that  they  are  different  in  their  liability  to  become  dis- 
eased. Owing  to  their  activity  and  to  their  important  functions,  the 
organs  are  more  subject  to  disease  than  are  the  spaces  and  side  ways 
through  which  the  vascular  trunks  pass  and  in  which  they  are  sus- 
pended like  pipes.  Disease  of  the  intima  is  a  characteristic  of  the 
arteries  and  veins  of  the  organs,  while,  on  the  other  hand,  there  is  a 
good  deal  of  evidence  tending  to  show  that  the  vascular  trunks  occu- 
pied in  carrying  the  blood  are  more  subject  to  primary  disease  of  the 
muscularis. 

Figs.  26  and  27  represent  a  small  fusiform  aneurism  of  the  sub- 
clavian  artery,  which  pulsated  violently  during  the  life  of  the  patient 
There  are  thickening  of  and  calcareous  deposit  in  the  muscularis  of 
the  artery.  It  is  strange  that  there  is  not  more  evidence  of  disease, 
for  the  pulsation  of  the  artery  was  always  very  violent  and  the  patient 
was  under  observation  for  several  years  and  died  of  an  intercurrent 
malady.  Fig.  26  demonstrates  little  except  that  the  wall  of  the  artery 
is  of  uneven  thickness.  Fig.  27  shows  the  muscular  tissue  to  be  more 
open  meshed  than  is  natural,  and  calcareous  material  can  be  seen  lying 
between  the  threads  of  muscular  tissue.  The  muscular  coat  is  thick- 
ened, but  it  would  certainly  be  unreasonable  to  suppose  that  such 
diseased  tissue  was  endowed  with  an  increase  of  power  to  contract. 
The  calcareous  deposit  which  is  scattered  in  small  particles  through 
the  arterial  wall  lies  in  the  muscular  tissue.  This  is  an  interesting 
and  instructive  fact,  because  it  has  been  said  by  some  authorities 
that  chalk  is  generally  first  deposited  in  the  plicated  membrane. 
The  plicated  membrane  is  a  striking  feature  of  the  appearance  of 
most  middle-sized  and  small  arteries.  In  properly  prepared  sections 
of  normal  arteries  it  is  easily  seen,  and  it  constitutes  an  important 
landmark,  for  it  sharply  separates  the  muscularis  from  the  intima.  It 


FIG.  26. — ANEURISM.     (X  8.) 

From  a  woman  forty-seven  years  old  who  died  of  obstruction  of  the  bowel.  The  section 
is  through  a  small  aneurism  of  the  right  subclavian  artery.  It  shrunk  a  good  deal  after 
death.  Much  of  the  tissue  stained  badly  and  the  lining  of  the  artery  is  loose  ;  this  is  perhaps 
a  post-mortem  change,  h  indicates  an  area  represented  more  highly  magnified  by  Fig.  27. 

FIG.  27. — ANEURISM.     (X  50.) 

The  region  indicated  by  h  in  Fig.  26.  The  three  coats  cannot  so  easily  be  distinguished 
as  they  generally  can  be  in  small  arteries.  The  appearance  approaches  more  nearly  to  that  of 
the  aorta,  in  which  there  is  never  a  distinct  plicated  membrane  separating  the  intimaand  mus- 
cularis.  i,  intima ;  m,  muscularis ;  and  a,  adventiti'a.  c  indicates  a  deposit  of  chalk.  The 
muscularis  is  loose-meshed,  and  there  is  less  muscular  tissue  than  is  natural,  and  a  good  deal 
of  chalk  can  be  seen  deposited  between  the  muscle-fibres. 


FIG.  26. 


FIG.  27. 


a  ^T~  '  -          . 


DISEASE  OF  BLOOD-VESSELS  IN  GENERAL  43 

is  considered  to  be  a  part  of  the  intima,  but  I  am  not  able  to  com- 
prehend why  this  should  be.  There  is  much  elastic  tissue  scattered 
through  the  muscularis  and  very  little  in  the  intima  of  arteries,  and 
this  seems  a  reason  why  the  plicated  membrane  might  more  reason- 
ably be  considered  to  belong  to  the  muscular  coat  than  to  the  intima. 
The  question  to  which  of  the  three  tunics  the  plicated  membrane 
properly  belongs,  or  if  it  has  a  separate  existence  of  its  own,  is  not 
easy  to  answer.  The  fact  that  this  question  of  anatomical  classifica- 
tion cannot  at  present  be  answered,  need  not,  however,  interfere  with 
the  progress  of  pathology,  for  not  knowing  exactly  how  to  classify  the 
membrane  will  not  interfere  with  the  observation  of  its  diseases.  The 
statement  has  been  made  that  calcareous  degeneration  of  the  arteries 
begins  in  the  plicated  membrane,  but  this  position  cannot  be  rigidly 
maintained.  My  own  observations  have  shown  me  that  chalk  may 
be  deposited  in  any  part  of  a  blood-vessel,  and  Fig.  27  demonstrates 
primary  chalky  deposit  in  the  muscularis.  Morbid  deposits  of  chalk 
may  occasionally  be  found  in  almost  all  parts  of  the  body,  and  it 
would  be  strange  if  the  chalk  were  always  deposited  first  in  the 
plicated  membrane  when  the  disease  occurs  in  the  blood-vessels. 
In  examining  sections  of  arteries  I  have  found  at  different  times 
chalky  deposits  in  all  three  of  the  tunics,  but  most  of  the  arteries 
that  one  has  the  opportunity  to  examine  are  those  in  which  the 
disease  has  proceeded  far  and  the  deposits  are  extensive.  Even  if  a 
section  is  obtained  in  which  chalky  deposit  is  found  confined  to  the 
plicated  membrane,  it  is  impossible  to  know  from  the  single  section 
that  the  deposit  is  not  a  part  of  a  large  one  which  extends  into  the 
other  coats.  Under  such  circumstances  it  is  not  possible  to  ascertain 
in  which  tunic  the  disease  originated.  Fig.  28  confirms  the  correct- 
ness of  this  statement.  It  is  one  of  a  set  of  serial  sections  of  the 
radial  artery  of  an  old  man.  Other  sections  of  the  series  show  that 
the  deposit  of  chalk  is  much  larger  than  it  appears  in  Fig.  28  and 
that  it  extends  far  into  the  muscularis  and  intima,  destroying  large 
portions  of  them.  Were  it  not  that  the  other  sections  show  that  the 
spot  of  calcareous  degeneration  is  such  a  large  one,  it  might  be 
thought  that  Fig.  28  confirms  the  view  that  calcareous  degeneration 
begins  in  the  plicated  membrane,  whereas  it  is  not  possible  from 
study  of  it  and  of  the  rest  of  the  series  of  sections  to  learn  in  which 
of  the  coats  the  chalk  was  first  deposited.  Incidentally  it  is  inter- 


44  HUMAN  BLOOD-VESSELS 

esting  that  there  arc  minute  chalky  deposits  scattered  through  the 
muscularis  of  Fig.  28  which  are  exactly  similar  to  those  shown  by 
Fig.  27.  For  some  reason  these  are  not  shown  by  the  illustration 
(Fig.  28). 

In  arteries  of  which  the  intima  is  thickened  it  is  common  for  the 
plicated  membrane  to  be  destroyed,  so  that  no  trace  of  it  can  be  seen 
at  those  parts  at  which  the  thickening  of  the  intima  is  greatest.  In 
other  diseased  arteries  it  is  quite  common  to  find  that  the  plicated 
/membrane  has  been  completely  destroyed.  It  presents  many  points 
/of  resemblance  to  the  cornea  of  the  eye,  which  in  a  natural  condition 
/  appears  to  be  structureless  and  without  cells,  but  becomes  opaque 
/  when  inflamed.  This  process  has  been  studied  in  the  lower  animals 
I  by  irritating  the  cornea  so  as  to  cause  inflammation.  Disease  which 
/  presents  changes  similar  to  those  that  arise  in  the  cornea  when  it  is 
irritated  occur  in  the  plicated  membrane.  I  believe  that  these 
changes  constitute  one  of  the  earliest  if  not  the  earliest  form  of  chronic 
disease  of  the  arteries.  This  subject  is  discussed  in  my  book  on  the 
"  Origin  of  Disease,"  l  and  the  illustrations  show  various  stages  of  the 
disease.  The  plicated  membrane,  which  in  its  healthy  state  is  clear 
and  glassy,  becomes  muddy  and  cells  become  distinguishable.  As 
the  process  progresses  its  transparency  is  lost,  and  it  is  so  much 
changed  in  character  that  it  can  no  longer  be  recognized.  The  cel- 
lular tissue  which  is  formed  from  the  plicated  membrane  appears  to 
become  a  part  of  the  thickened  intima.  Although  often  thus  destroyed 
and  contributing  a  portion  toward  the  formation  of  thickenings  of  the 
intima,  it  frequently  happens  that  the  intima  is  greatly  thickened  and 
diseased  and  yet  the  plicated  membrane  remains  to  form  a  distinct 
boundary  separating  the  muscularis  from  the  intima  ("  Origin  of  Dis- 
ease," Figs.  10  and  11).  The  growth  of  cells  in  the  plicated  mem- 
brane and  its  destruction  by  being  converted  into  a  completely  cellular 
tissue  indistinguishable  from  the  intima  occur  in  chronic  disease  at  all 
periods  of  life. 

Disease  of  the  intima  is  of  more  frequent  occurrence  than  disease 
of  the  other  vascular  tunics,  and  the  commonest  form  of  it  is  the  thick- 
ening which  is  called  endarteritis.  As  syphilis  used  to  be  supposed 
to  be  the  most  frequent  cause  of  endarteritis,  it  is  necessary,  as  has 

1  Page  42  and  Figs.  7,  8,  9,  lo,  and  n. 


FIG.  28. — CALCAREOUS  DEPOSIT  IN  THE  RADIAL  ARTERY.     (X  105.) 

A  section  of  the  radial  artery  of  a  man  sixty  years  old  who  died  of  endocarditis  and  car- 
diac dilatation,  i,  intima ;  p,  plicated  membrane  ;  ;«,  muscularis  ;  a,  adventitia.  Toward 
the  left  the  plicated  membrane  enlarges  and  becomes  obscured  by  the  deposit  of  the  chalk, 
which  is  distinctly  shown. 


FIG.  28. 


DISEASE  OF  BLOOD-VESSELS  IN  GENERAL  45 

already  been  pointed  out,  to  remember  that  syphilitic  endarteritis 
cannot  be  distinguished  from  endarteritis  due  to  other  causes.  It 
should  also  be  kept  in  mind  that  thickening  of  the  intima  of  the 
arteries  is  the  commonest  change  that  takes  place  in  the  blood- 
vessels as  life  advances,  and  that  it  is  of  frequent  occurrence  in 
young  persons  and  even  in  infancy  in  cases  of  chronic  disease.  The 
study  of  disease  of  the  intima  is  made  difficult  at  present  by  the  fact 
that  there  is  no  accepted  standard  to  establish  what  is  a  normal  intima. 
In  text-books  of  histology  there  are  pictures  and  descriptions  of  the 
intima  of  various  blood-vessels  and  of  it  in  vessels  of  different  sizes, 
but  no  account  is  taken  of  the  fact  that  with  the  progress  of  years 
there  is  in  all  human  beings  a  tendency  for  the  intima  to  become 
thicker.  This  tendency  is  so  universal  that  there  cannot  be  any  doubt 
of  its  existence.  The  lack  of  a  standard  of  the  normal  makes  it 
difficult  in  individual  cases  to  decide  whether  a  particular  change 
of  the  intima  that  is  being  studied  is  really  disease  and  was  injurious, 
or  if  it  is  so  slight  that  it  must  be  regarded  as  merely  the  natural  result 
of  the  passage  of  time  and  therefore  harmless.  This  difficulty  is 
very  real  to  any  one  who  has  studied  disease  of  the  blood-vessels, 
and  sometimes  it  is  impossible  to  find  a  conclusive  and  satisfactory 
solution  of  it  The  subject  of  the  bodily  changes  incident  to  the 
advance  of  years  I  discussed  in  my  book  on  the  "  Origin  of  Disease," 
and  in  the  chapter  on  the  "  disease  of  age  "  I  tried  to  demonstrate  that 
such  a  thing  as  a  physiological  old  age  has  no  existence.  The 
changes  of  the  organs  and  of  the  tissues  that  come  with  advancing 
years  are  as  real  and  as  visible  to  the  eye,  if  sought  for,  as  the  lesions 
which  are  due  to  any  of  the  common  diseases,  and  these  physical 
changes  inevitably  attendant  upon  the  increase  of  years  necessarily 
weaken  the  individual,  and  in  time,  when  they  have  progressed  suf- 
ficiently far,  they  must  cause  death.  It  is,  however,  quite  impossible 
to  forecast  the  rate  at  which  the  changes  due  to  age  will  progress. 

Disease  of  the  intima  can  hardly  occur  without  causing  some  thick- 
ening of  the  vessel-wall  and  this  thickening  mustxreduce  the  calibre 
of  the  affected  vessel.  There  is  no  escape  from  the  conviction  that 
reduction  in  size  of  its  calibre  must  take  away  from  a  blood-vessel  its 
state  of  physiological  perfection.  As  men  increase  in  years  the  intima 
of  the  arteries  thickens  as  surely  as  the  face  becomes  wrinkled  and 
other  changes  occur  which  make  it  possible  to  distinguish  an  old  man 


46  HUMAN  BLOOD-VESSELS 

from  a  young  one.  Although  this  thickening  of  the  intima  must 
reduce  the  size  of  the  calibres  of  the  affected  blood-vessels,  it  is  not 
well  to  be  hypercritical,  and  pathologists  should  not  exaggerate  its 
importance,  for  if  moderate  in  degree  there  is  every  reason  to  think 
it  harmless.  At  the  same  time  there  cannot  be  any  doubt  that  the 
process  is  a  disease.  The  lexicon  of  the  New  Sydenham  Society 
defines  disease  as  "  a  departure  from  the  state  of  health,  especially 
when  caused  by  structural  change."  If  this  definition  be  accepted 
as  correct,  thickening  of  the  intima  of  the  arteries  is  a  disease.  Al- 
though there  is  every  reason  to  believe  that  the  disease  in  its  lesser 
degrees  does  no  appreciable  harm,  it  is  quite  certain  on  the  other  hand 
that  greatly  narrowed  arteries  and  veins  cannot  perform  their  functions 
in  a  perfect  manner.  The  intima  is  often  so  thick  that  it  alone  is  of 
greater  diameter  than  the  other  two  tunics  together,  and  under  such 
circumstances  the  vessel  must  lose  efficiency  both  because  of  the 
reduction  in  the  size  of  the  opening  and  because  its  elasticity  and  its 
power  of  contractility  are  reduced.  Almost  all  of  the  elastic  tissue  is 
in  the  muscularis  and  adventitia,  and  the  freedom  of  motion  of  these 
two  coats  which  surround  the  intima  must  be  greatly  reduced  when 
the  intima  is  morbidly  thickened.  Whatever  service  the  elasticity 
and  contractility  of  the  blood-vessels  may  perform,  the  perfection 
of  action  must  be  interfered  with  by  any  great  thickening  of  the 
intima. 

Fig.  29  is  a  drawing  of  part  of  a  section  through  the  wall  of  the 
radial  artery,  and  the  intima  and  a  portion  of  the  muscularis  are  in- 
cluded. There  is  a  clot  inside  the  vessel  which  is  attached  to  it  by 
threads  of  tissue  which  penetrate  quite  deeply  into  the  intima.  The 
formation  of  clots  within  the  blood-vessels  is  a  disease  process  of  im- 
portance, and  it  probably  occurs  frequently  and  at  all  periods  of  life. 
There  is  good  reason  to  believe  that  the  deposit  of  clots  within  the 
vessels  sometimes  contributes  a  part  and  perhaps  a  large  part  toward 
causing  thickening  of  the  intima.  This  subject  is  discussed  in  my 
book  on  the  "  Origin  of  Disease"  (page  57).  Fig.  29  shows  thickening 
of  the  intima  of  moderate  degree.  The  tissue  is  a  good  type  of  what 
is  usually  formed  as  a  result  of  disease  of  this  nature,  and  is  quite 
unlike  any  of  the  normal  human  tissues.  It  is  different  from  the 
ordinary  forms  of  connective  tissue  and  is  more  like  epithelium  than 
anything  else,  but  is  in  some  respects  different  from  normal  epithelium. 


FIG.  29. — ORGANIZED  CLOT  ATTACHED  TO  THE  INTIMA  OF  AN  ARTERY.      (X  240.) 

From  the  same  case  as  Figs.  36,  37,  and  42, — a  negro  woman  twenty-seven  years  old 
who  died  of  typhoid  fever.  A  section  extending  part  way  through  the  radial  artery  ;  the 
adventitia  is  not  included  and  only  part  of  the  muscularis.  The  artery  is  not  normal,  for  the 
intima  is  unnaturally  thick,  m,  muscularis  ;  p,  plicated  membrane ;  i,  intima  ;  <r,  clot,  which 
contains  cells  that  were  living,  and  there  are  threads  extending  into  the  intima  and  attaching 
the  clot  to  the  lining  of  the  artery. 


DISEASE  OF  BLOOD-VESSELS  IN  GENERAL  47 

There  is  probably  no  other  disease  of  the  blood-vessels  which  has 
been  so  extensively  studied  and  so  much  discussed  as  atheroma.  I 
have  found  the  term  somewhat  differently  defined  in  dictionaries. 
The  best  definition  is  that  given  by  the  Century  Dictionary,  and  it  is 
as  follows  :  "  I.  A  name  given  to  various  kinds  of  encysted  tumors, 
the  contents  of  which  have  the  appearance  of  bread-sauce.  2.  The 
formation  of  thickened  patches  of  the  inner  coat  of  an  artery  (much 
more  rarely  of  a  vein),  constituting  flattened  cavities  which  contain  a 
pasty  mass  exhibiting  fat-globules,  fatty  acid  crystals,  cholesterin, 
more  or  less  calcareous  matter,  etc.  The  endothelial  film  separating 
this  from  the  blood  may  give  way,  and  an  atheromatous  ulcer  be 
formed."  The  derivation  of  the  term  atheroma  is  from  a  Greek  word 
meaning  a  gruel.  It  is  evident  from  this  that  the  term,  as  commonly 
used  to  designate  the  disease  of  the  arteries  to  which  it  is  applied,  is 
employed  in  quite  a  different  sense  from  its  original  one.  The  lexi- 
con of  the  New  Sydenham  Society  gives  the  original  significance 
of  the  word  atheroma  and  then  says  that  the  "  term  is  also  used 
alone  to  signify  a  different  disease,  atheroma  of  the  arteries,"  and 
refers  to  "  arteritis  "  for  a  detailed  description.  Under  the  head 
"  arteritis  "  it  describes  various  forms  of  atheroma  of  arteries,  evidently 
meaning  to  convey  the  impression  that  all  kinds  of  it  are  varieties 
of  inflammation,  although  no  direct  statement  to  that  effect  is  made. 
It  has  grown  to  be  the  custom  of  recent  years  to  designate  by  the 
word  atheroma  most  of  the  common  changes  of  the  lining  of  arteries 
which  can  be  distinguished  with  the  unaided  eye  and  which  occur  also 
in  the  veins,  but  it  has  been  supposed  much  less  frequently.  Under 
it  are  included  abscesses,  ulcers,  thickenings,  patches,  and  calcareous 
deposits, — in  short,  almost  every  change  of  the  lining  of  blood-vessels 
which  can  be  seen  without  the  microscope.  When  the  many  forms 
of  disease  thus  called  atheroma,  and  which  have  been  included  under 
a  single  head,  are  studied  microscopically,  they  are  variously  subdi- 
vided in  accordance  with  the  nature  of  their  causes  and  formation. 
Most  of  them  are  the  result  of  acute  or  chronic  inflammation,  if  in- 
flammation be  accorded  its  broader  and  more  comprehensive  meaning. 
It  is  astonishing  how  little  is  known  of  the  effects  of  these  changes 
of  the  lining  of  the  blood-vessels.  It  is  not  rare  to  see  old  men  in 
the  enjoyment  of  good  health,  with  all  the  arteries  near  the  surface 
tortuous  and  hard  and  the  surface  veins  distended  and  rigid  to  the 


48  HUMAN  BLOOD-VESSELS 

touch,  and,  on  the  other  hand,  to  find  post  mortem,  in  persons  in 
whom  there  had  not  been  the  slightest  clinical  evidence  to  indicate  the 
existence  of  such  a  thing,  that  the  internal  blood-vessels  are  greatly 
diseased.  Although  the  economy  is  wonderfully  tolerant  at  times  of 
extensive  vascular  disease,  there  cannot  be  any  doubt  that  disease  of 
the  blood-vessels  does  produce  most  important  ill  effects  and  that 
their  state  of  well-being  is  necessary  to  good  health.  The  fact  that 
so  little  is  known  as  yet  of  the  effects  of  disease  of  the  blood-vessels 
should  make  pathologists  patient,  and  should  encourage  them  to  be 
willing  to  continue  the  objective  study  of  vascular  disease  and  to 
record  its  various  appearances  without  expecting  at  present  to  be 
able  to  explain  the  effects  of  the  lesions  found.  From  the  foregoing, 
it  is  evident  that  the  word  atheroma  has  been  used  in  a  somewhat 
loose  sense,  and  that  when  precision  of  meaning  is  wanted  the  term  is 
an  unsatisfactory  one. 

On«  of  the  commonest  causes  of  death  in  persons  over  fifty  years  of 
age  is  cerebral  hemorrhage,  and  it  is  generally  the  result  of  disease 
of  the  intima  of  the  arteries.  I  cannot  express  my  views  upon  the 
subject  better  than  by  the  following  quotation  from  my  book  on  the 
"Origin  of  Disease"  (page  172):  "It  is  my  opinion  that  in  apoplexy 
ulceration  of  the  blood-vessels  is  most  commonly  the  precedent 
disease.  This  causes  slowly  increasing  thinning  of  the  arterial  wall, 
until  perforation  takes  place  without  strain  or  violence.  Apoplexy 
is  not  usually  due  to  the  rupture  of  a  stiffened  and  weak  vessel 
caused  by  muscular  effort,  nor  does  it  commonly  occur  because  the 
heart  has  for  some  reason  driven  the  blood  onward  with  unusual 
force.  In  most  cases  neither  violence  nor  effort  has  any  influence  in 
causing  the  final  rupture  of  the  artery,  for  generally  apoplexy  comes 
on  while  the  individual  is  sitting  quietly  or  even  lying  down.  The 
process  is  one  of  ulceration,  exactly  similar  to  perforation  of  the  in- 
testine in  typhoid  fever,  where  rupture  takes  place  as  the  patient  lies 
quietly  in  bed.  In  several  cases  of  cerebral  apoplexy  which  have 
come  under  my  notice,  the  blood-vessels  were  found  ulcerated  and 
thinned,  and  in  one  the  vessel  at  the  seat  of  hemorrhage  was  found 
in  this  condition  of  ulceration,  with  the  opening  in  it  still  visible." 
The  belief  which  commonly  prevails,  that  some  physical  effort,  or  a 
disturbance  of  function  causing  the  heart  to  beat  with  unusual  vio- 
lence, is  generally  the  immediate  cause  of  apoplexy,  is  without  foun- 


DISEASE  OF  BLOOD-VESSELS  IN  GENERAL  49 

dation.  The  hemorrhage  results  from  an  ulcerative  process,  which 
is  generally  of  chronic  rather  than  of  acute  character,  and  often  is 
quite  latent  in  its  manner  of  progress.  Although  it  is  true  that  the 
ulceration  of  the  vessels  which  is  antecedent  to  cerebral  hemorrhage 
is  often  latent,  yet  it  is  not  always  entirely  so,  for  it  is  not  rare  that 
fatal  apoplexy  is  preceded  by  certain  symptoms  which  are  well 
known  to  clinicians. 


THE  information  that  can  be  obtained  in  regard  to  disease  of  the 
veins  is  meagre  and  is  not  precise  ;  it  is  therefore  unsatisfactory. 
What  is  known  of  the  subject  has  been  better  formulated  for  the 
clinician  than  for  the  pathologist.  It  is  possible  to  ascertain  from 
text-books  the  gross  pathological  appearances  usual  in  certain  known 
diseases  of  the  veins,  but  the  pathological  histology  of  disease  of  the 
veins  has  not  been  systematically  recorded.  A  careful  collection  and 
a  systematic  record  of  what  is  known  are  very  much  to  be  desired, 
but  the  task  of  making  such  a  collection  and  record  is  one  I  have 
not  undertaken,  and  I  shall  not  attempt  more  than  to  describe  the 
peculiarities  of  veins  that  I  have  myself  seen.  In  text-books  there 
may  be  found  descriptions  of  calcareous  deposits  in  veins,  of  phlebitis, 
ofendophlebitis,  of  hyperplastic  phlebitis,  and  other  diseases  to  which 
veins  are  subject,  but  the  descriptions  are  incomplete.  What  I  have 
learned  of  the  diseases  of  veins,  beyond  reading  such  descriptions,  has 
been  gained  almost  entirely  from  post-mortem  study,  and  not  from 
the  study  of  disease  of  veins  during  life. 

In  cases  of  fibrosis  of  the  veins  the  appearances  are  most  inter- 
esting and  curious.  Just  as  happens  to  the  arteries,  the  veins  are  in- 
volved when  the  fibroid  process  is  extensive,  and  in  the  case  of  the 
veins,  as  well  as  of  the  arteries,  it  is  often  impossible  to  decide  whether 
the  disease  originated  in  the  blood-vessels  or  outside  of  them  and 
independently.  The  general  subject  of  morbid  fibrosis  is  a  very  large 
one  and  one  of  the  utmost  importance,  but,  as  I  have  already  dis- 
cussed it  at  considerable  length  in  my  book  on  the  "Origin  of  Dis- 
ease" (page  9),  it  is  unnecessary  to  repeat  what  is  there  included. 
Figs.  30  and  3 1  represent  a  curious  form  of  fibroid  disease  of  a  vein. 
Fig.  30  shows  a  radial  artery  and  the  two  veins.  The  artery  is  thick 
walled,  but  it  presents  no  unusual  features,  and  the  condition  will  be 
described  in  the  chapter  on  disease  of  radial  arteries  and  veins.  Fig. 
3 1  is  a  more  highly  magnified  view  of  the  vein  to  the  right  in  Fig.  30. 
The  vein  is  thick  walled,  and  it  is  easy  to  see  that  much  of  the  in- 
crease of  thickness  is  due  to  the  growth  of  morbid  fibroid  tissue. 
So 


FIG.  30. — DISEASED  RADIAL  ARTERY  AND  VEINS.     (X  20.) 

From  a  negro  woman  of  twenty-three  who  died  of  ulcerative  endocarditis.  The  artery  is 
in  the  centre  and  the  veins  are  upon  either  side  of  it.  The  vein  to  the  right  is  represented 
more  highly  magnified  by  Fig.  31.  The  three  vessels  are  all  thickened.  They  probably 
shrunk  a  good  deal  post  mortem. 

FIG.  31. — FIBROID  DEGENERATION  OF  A  VEIN.      (X  105.) 

A  vein  from  Fig.  30  more  highly  magnified.  There  is  a  large  clot  in  the  lumen,  a, 
adventitia ;  in,  muscularis.  It  is  loose-textured,  instead  of  being  a  closely  woven  tissue,  as 
normal  involuntary  muscle  usually  is.  Between  the  darker  strands  of  the  muscular  fibres  is 
a  light-colored  tissue  containing  nuclei, — this  is  morbid  fibroid  tissue,  i,  intima,  which  has 
upon  its  inner  surface  a  fringe  of  bead-like  nuclei  which  lie  in  folds.  This  folding  was 
probably  caused  by  post-mortem  shrinkage,  b,  a  minute  capillary  ;  f,  an  area  of  fibroid 
deposit  in  which  the  nuclei  are  set  across  the  circle  formed  by  the  wall  of  the  vein.  Near 
this  region  the  muscular  fibres  are  torn  apart,  and  there  is  an  opening  through  the  strands  of 
muscle  just  below  the  capillary  b.  It  looks  as  if  morbid  fibroid  tissue  had  invaded  the 
muscularis  of  the  vein  from  the  perivascular  connective  tissue,  just  as  cancer  progresses  by 
forcing  its  epithelioid  cells  into  surrounding  tissues. 


FIG.  30. 


FIG.  31. 


•V  '  .,  .       ' 


DISEASE  OF  VEINS  51 

The  adventitia,  the  muscularis,  and  the  intima  are  easily  distin- 
guished. The  adventitia  presents  no  notable  features  and  the  intima 
is  slightly  thickened,  but  the  muscularis  is  very  thick  and  is  much 
diseased.  The  muscular  tissue  is  disposed  in  irregular  bands  of  various 
sizes,  and  these  are  of  different  lengths,  and  the  spaces  between  the 
strands  of  muscle  are  filled  with  fibrous  tissue.  It  is  quite  unlike  any 
natural  involuntary  muscular  tissue  and  I  have  never  seen  similar 
disease  of  arteries.  It  looks  as  if  the  fibrous  tissue  of  the  adventitia 
or  the  perivascular  fibrous  tissue  had  insinuated  itself  into  the  muscu- 
laris of  the  vein  and  had  torn  and  split  the  strands  of  muscle  apart. 
To  the  right  in  the  picture  there  is  an  opening  in  the  muscularis  in 
which  many  nuclei  of  fibroid  tissue  can  be  seen,  and  it  seems  as  if  this 
fibrous  tissue  had  grown  from  the  outside  through  the  opening  into 
the  muscular  tissue.  The  effect  produced  is  very  like  that  which  is 
often  seen  at  the  margin  of  a  cancer  when  the  cells  of  the  new  growth 
force  themselves  into  the  surrounding  tissue,  overwhelming  it  and 
changing  its  character  as  the  cancer  extends.  This  appearance  of  a 
growing  cancer  at  the  margin  is  very  familiar  to  those  who  have 
studied  pathological  histology.  In  the  vein,  Fig.  3  i,  the  line  of  sepa- 
ration of  the  muscularis  from  the  adventitia  is  less  sharply  marked 
than  in  normal  vessels.  The  outer  boundary  of  the  muscular  coat  is 
broken  by  openings  in  the  muscle  which  are  filled  with  fibrous  tissue. 
There  is,  of  course,  no  line  of  separation  between  adventitia  and 
perivascular  connective  tissue.  Fibroid  disease  of  a  vein  of  such  a 
nature  makes  one  think  again  of  the  enlightening  essays  of  Gull  and 
Sutton  on  arteriocapillary  fibrosis.  They  did  not  make  an  exact 
demonstration,  but  their  observations  were  the  first  to  draw  attention 
to  the  importance  of  the  disease  whose  visible  manifestation  is  morbid 
fibrosis.  The  disease  fibrosis  is  not  understood  further  than  that  it  is 
recognized  that  there  is  a  tendency  sometimes  for  fibrous  tissue  to 
grow  where  it  ought  not  and  cannot  without  injury  to  the  organs  or 
tissues  affected.  This  morbid  tendency  to  the  growth  of  fibroid  tissue 
presents  many  points  of  resemblance  to  the  malignant  diseases  can- 
cer and  sarcoma,1  of  the  causes  of  which  nothing  is  yet  really  known 
except  that  cancer  is  the  result  of  the  irregular  growth  of  epithelium 
and  sarcoma  of  the  irregular  growth  of  mesoblastic  tissue.  Many 

1  Origin  of  Disease,  by  Arthur  V.  Meigs,  page  20. 


52  HUMAN  BLOOD-VESSELS 

pathologists  think  there  is  an  extrinsic  cause,  but  there  is  no  reason 
for  such  a  belief  unless  the  fact  that  it  is  hard  to  understand  how 
cancer  and  sarcoma  could  begin  without  an  extrinsic  cause  be  con- 
sidered a  reason.  To  assert  the  existence  of  an  extrinsic  cause 
because  no  other  explanation  is  at  hand  is  unscientific  and  is 
quite  unwarranted.  Morbid  fibrosis  is  a  disease  of  great  importance, 
and  it  is  to  be  hoped  that  more  will  be  learned  of  its  causes  and 
effects. 

Fig.  32  depicts  a  vein  from  the  margin  of  an  ulcer  of  the  ankle 
which  had  thickened  edges.  It  was  removed  by  operation  from  the 
living  patient.  With  the  unaided  eye  it  was  seen  that  the  vessel  had 
thick  walls  and  a  very  small  opening.  The  disease  was  purely  local 
and  was  thought  to  be  due  to  sluggish  inflammation  or  to  syphilis. 
The  illustration  shows  great  fibroid  thickening  of  the  vein.  It  is  diffi- 
cult to  recognize  the  three  tunics,  and  their  lines  of  separation  from 
one  another  are  quite  lost.  The  intima  is  thickened  and  it  is  of 
unnatural  appearance.  Muscular  tissue  can  be  distinctly  recognized, 
but  the  strands  are  separated  so  that  it  looks  as  if  it  had  been  torn  and 
distorted  like  the  muscular  tissue  of  Fig.  31,  but  even  more  so,  for  the 
greater  part  of  the  tissue  composing  Fig.  32  is  fibrous.  There  are 
minute  blood-vessels  in  the  adventitia  and  two  or  three  nerve-fibres 
which  were  cut  across.  It  seems  impossible  to  explain  the  appear- 
ance except  on  the  theory  that  the  effect  was  produced  by  the  growth 
of  morbid  fibroid  tissue  in  the  walls  of  a  vein  that  was  once  normal. 
From  the  appearance  only  of  this  vessel  it  would  be  impossible  to  be 
certain  that  it  was  a  vein  and  not  an  artery,  but  it  was  distinctly 
recognized  to  be  a  vein  in  the  tissue  of  the  living  patient,  and  when 
cut  contained  venous  blood.  I  have  never  myself  seen  an  artery 
affected  in  a  similar  way,  but  am  unable  to  say  whether  arteries  ever 
are  so  diseased. 

Fig-  33  represents  an  artery  and  a  vein  of  the  kidney.  The  sec- 
tion was  cut  without  any  disturbance  of  the  natural  arrangement  of 
the  parts  ;  the  two  vessels  are  therefore  surrounded  by  the  kidney 
tissue  just  as  they  were  during  the  life  of  the  patient.  A  most 
curious  form  of  fibrosis  is  exhibited  by  the  two  vessels.  The  artery 
is  a  type  of  the  form  of  disease  which  most  commonly  affects 
the  arteries  of  fibroid  kidneys.  The  wall  is  thick  and  the  calibre 
small.  The  intima  is  much  thicker  than  is  normal  and  is  of  irregu- 


FIG.  32. — ENDOPHLEBITIS.      (X  50.) 

From  a  man  of  thirty-nine  years.  The  vein  was  cut  during  life  from  the  margin  of  an 
acute  ulcer  of  the  ankle.  The  ulcer  had  thickened  raised  edges.  The  wall  of  the  vein  is 
greatly  thickened  and  the  lumen  a  mere  slit.  Although  the  disease  was  acute,  the  changes 
are  very  like  those  shown  by  Figs.  34  and  35.  In  this  case  it  is  difficult  to  make  a  precise 
differentiation  cf  the  three  coats.  The  tissue  is  loose-meshed  and  contains  many  nuclei,  as  is 
usual  in  rapidly  growing  structures. 


FIG.  32. 


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FIG.  33. — DISEASED  ARTERY  AND  VEIN  OF  THE  KIDNEY.     (X  50.) 

From  a  woman  forty-seven  years  old  who  died  of  obstruction  of  the  bowel.  The  kidney 
is  fibroid  and  the  blood-vessels  lie  in  a  fibroid  area.  The  artery  shows  in  typical  form  the 
thickening  that  is  common  in  the  kidney,  which  in  this  instance  is  of  moderate  degree.  The 
intima  is  irregularly  thickened  and  the  muscularis  also  is  a  little  thicker  than  normal. 
Outside  the  muscularis  is  the  adventitia,  which  consists  of  fibroid  tissue,  and  it  is  impossible 
to  say  where  the  adventitia  ends  and  the  perivascular  connective  tissue  begins,  for  there  is  no 
line  of  separation.  Above  the  artery  is  the  vein,  and  its  appearance  is  striking  and  very 
peculiar.  Its  wall  is  a  ring  of  endothelium  surrounded  by  fibrous  tissue.  There  is  no  differ- 
entiation between  the  wall  of  the  vein  and  the  surrounding  morbid  fibrous  tissue  of  the  kidney. 
The  vein  must  at  one  time  have  had  a  distinct  wall  with  muscular  tissue  in  it.  Disease 
sometimes  produces  an  effect  like  this  in  the  spleen.  See  Fig.  92. 


FIG.  33. 


DISEASE  OF  VEINS  53 

]ar  thickness  at  different  parts.  The  muscularis  is  a  little  thicker 
than  natural  and  is  irregularly  thick.  The  irregularity  of  thickness 
of  the  intima  and  muscularis  is  certainly  abnormal.  The  adven- 
titia  and  the  perivascular  connective  tissue  are  absolutely  indistin- 
guishable, and  therefore  it  is  impossible  to  say  whether  or  not  the 
adventitia  is  thickened.  The  vein,  as  it  is  seen  in  cross-section, 
appears  as  a  ring  of  endothelium  surrounded  by  dense  fibrous  tissue. 
There  is  nothing  to  indicate  that  there  ever  were  three  coats.  The 
fibrous  tissue  is  not  like  the  natural  adventitia  of  blood-vessels,  and  it 
is  continuous  with  the  morbid  fibroid  tissue  of  the  diseased  kidney 
and  with  that  around  the  artery.  There  is  no  line  of  separation  of 
the  adventitia  of  this  artery  and  vein  from  the  perivascular  con- 
nective tissue  surrounding  them.  They  furnish,  therefore,  a  good 
illustration  to  support  the  opinion  that  has  been  expressed  (page 
6)  that  blood-vessels  should  be  described  as  having  only  two 
coats,  the  intima  and  the  muscularis,  and  that  the  adventitia  should 
be  regarded  as  a  part  of  the  perivascular  connective  tissue.  It 
is  impossible  from  the  study  of  blood-vessels  like  these  two  to 
decide  whether  the  fibroid  disease  that  they  exhibit  originated  in 
them  or  in  the  surrounding  tissue  and  later  included  them  in  the 
course  of  its  extension.  In  this  case  the  vein  is  much  more  diseased 
than  the  artery,  for  although  the  three  tunics  are  thickened  and 
diseased  in  the  artery  they  are  easily  distinguishable  because  they 
retain  their  characteristic  appearances,  but  the  vein  is  a  mere  channel 
in  fibrous  tissue.  It  would  be  impossible  to  recognize  it  as  a  vein 
were  it  not  for  its  situation  beside  the  artery.  The  endothelial  lining 
and  the  blood-corpuscles  which  lie  within  the  calibre  would  not  enable 
any  one  to  be  sure  it  is  a  vein.  Blood-vessels  so  greatly  changed  as 
this  vein  is  cannot  be  recognized  except  by  their  situation  or  by 
some  other  characteristic  that  remains  unaltered  by  the  disease. 
Veins  and  arteries  become  indistinguishable  when  greatly  diseased. 
Although  the  walls  of  veins  are  usually  thinner  than  those  of  arteries, 
it  is  not  rare  to  find  diseased  veins  with  walls  as  thick  as  those  of 
their  accompanying  arteries.  Fig.  75  depicts  such  a  vein  and  artery  ; 
but  they  are  more  fully  described  at  page  87.  Veins  like  this  one 
are  generally  found  to  have  undergone  extensive  fibroid  infiltration 
of  the  muscularis. 

Figs.  34  and  35  represent  disease  of  a  vein.     The  illustrations  have 


54  HUMAN  BLOOD-VESSELS 

already  been  published.1  They  are  drawings  of  the  same  vein,  which 
was  removed  during  life  from  the  dorsum  of  the  foot  of  a  man  twenty- 
five  years  old.  Fig.  34  shows  fibroid  disease  in  many  respects  like 
that  shown  by  Figs.  3 1  and  3  2,  which  has  already  been  described.  Fig. 
35  exhibits  another  curious  disease  to  which  veins  are  subject — pro- 
liferation of  the  intima.  This  proliferation  is  sometimes  extraordinarily 
great,  and  I  have  found  it  in  the  radial  and  in  other  veins  as  well  as 
in  this  one.  The  intima  grows  so  rapidly  that  its  proliferation  out- 
strips that  of  the  other  tunics,  and  it  becomes  separated  from  the 
muscularis  and  fills  the  lumen,  so  that  when  the  vein  is  examined  in 
cross-section  the  proliferated  intima  looks  like  a  bundle  of  earth- 
worms. There  is  not  generally  a  distinct  plicated  membrane  in  veins, 
as  there  is  in  arteries  ;  but  the  enormously  proliferated  and  convo- 
luted intima  that  is  shown  by  the  drawing  is  composed  of  a  glassy 
and  nearly  homogeneous  membrane  with  endothelial  plates  upon  its 
edges,  which  is  structurally  like  the  plicated  membrane  as  it  is  some- 
times seen  in  arterioles  in  the  earlier  stages  of  endarteritis.  I  have 
never  seen  this  excessive  proliferation  with  convolution  of  the  lining  in 
an  artery ;  but  there  is  nothing  at  present  known  to  explain  why  the 
disease  should  be  peculiar  to  veins.  The  peculiarities  of  the  vein 
which  is  shown  by  Figs.  34  and  35  are  described  and  the  clinical  his- 
tory of  the  patient,  who  was  a  man  twenty-five  years  old,  is  given  in 
the  essay  on  endophlebitis  which  has  already  been  cited.  From  that 
essay  I  shall  quote  : 

"  A  small  vein  which  extended  across  the  right  foot  about  an  inch 
from  the  roots  of  the  toes,  and  which  received  branches  from  the  su- 
perficial veins  of  the  toes,  could  be  felt  to  be  distinctly  thickened. 
As  this  vein  lay  directly  beneath  the  skin,  its  unnatural  thickness  could 
easily  be  distinguished  by  passing  the  finger  back  and  forth  across  it, 
especially  where  it  crossed  the  tendons,  which  made  a  firm  back- 
ground against  which  to  press  it.  It  felt  like  a  minute  cord,  instead  of 
almost  disappearing  when  compressed,  as  a  healthly  vein  will  do  when 
felt  through  the  skin.  The  corresponding  vein  of  the  left  foot  also 
was  much  thicker  than  natural,  but  less  than  the  one  that  has  been 
described.  As  the  patient  said  he  was  quite  willing,  a  short  incision 

1  Endophlebitis,  by  Arthur  V.  Meigs,  Journal  of  Anatomy  and  Physiology,  vol.  xxxiv., 
July,  1890,  page  458 ;  and  Transactions  of  the  Pathological  Society  of  Philadelphia, 
November  9,  1899. 


FIG.  34. — DISEASED  VEIN.     (X  56.) 

From  the  dorsum  of  the  foot  of  a  man  of  twenty-five  years.  Removed  by  operation.  The 
vein  is  almost  closed  by  thickening  of  the  muscularis.  The  thickened  muscularis  is  only 
partly  composed  of  true  muscular  tissue,  which  has  been  torn  apart  and  thrown  into  wavy 
strands  by  morbid  fibroid  tissue  which  has  grown  in  it.  x,  the  line  of  separation  of  the 
fibrous  coat  from  the  muscularis ;  y,  the  line  of  separation  of  the  muscularis  from  the  intima. 
All  the  tissue  between  x  and  y  is  muscularis  ;  the  thickening  of  it  is  very  great.  At  y  the 
separation  of  muscularis  from  intima  is  clearly  marked,  but  at  other  parts  of  the  circuit  there 
is  no  distinguishable  boundary-line.  .  The  intima  is  thickened,  but  not  so  much  as  the  muscu- 
laris. The  lining  is  beaded  with  enthothelial  nuclei,  z  is  an  area  represented  more  highly 
magnified  by  D. 

FIG.  35. — DISEASED  VEIN.      (X  56.) 

Another  section  of  the  vein  shown  by  Fig.  34.  There  is  great  thickening  of  the  wall,  but  it 
is  of  a  different  character.  The  opening  is  almost  filled  by  irregular  projections  from  the  intima. 
One  of  these  (o)  is  curiously  folded  and  knotted.  There  is  another  somewhat  similar  knot  of 
smaller  size,  and  several  irregularly  shaped  projections  of  the  intima,  which  fill  a  large  por- 
tion of  the  lumen.  The  muscularis  is  irregularly  thickened.  Parts  of  it  are  hard  to  recog- 
nize as  involuntary  muscle,  being  more  like  morbid  fibroid  tissue,  p  is  distinctly  muscular 
tissue,  m  shows  the  muscularis  and  intima  shading  together  without  a  distinguishable  line  of 
separation.  «  marks  a  spot  where  the  separation  of  the  two  coats  is  distinct. 

C.  (X  220) . — A  portion  of  the  muscularis  from  Fig.  34  more  highly  magnified.  It  shows, 
the  character  of  the  long  and  narrow  nuclei  of  the  involuntary  muscle. 

D  (X  220). — The  region  z  from  Fig.  34  more  highly  magnified.  The  central  por- 
tion is  morbid  fibroid  tissue,  showing  a  fine  mesh  and  containing  a  single  connective-tissue 
nucleus.  Outside  of  this  is  muscular  tissue  containing  elongated  muscular  nuclei.  It  shows 
the  manner  in  which  the  muscular  tissue  is  torn  apart  by  the  growth  of  morbid  fibrous  tissue. 


tfg.34 


55 

was  made  through  the  skin,  and  a  small  piece  of  the  thickened  vein 
was  removed  from  the  right  foot.  In  the  removal  blue  venous  blood 
was  seen  in  the  vessel,  proving  that  it  was  a  vein.  When  the  cut  end 
of  the  vein  was  examined  with  a  hand  lens,  it  was  seen  to  be  almost 
solid  ;  there  remained  only  a  very  small  opening. 

"The  illustrations  are  etchings  which  were  made  with  the  camera 
lucida  ;  the  images  of  the  objects  under  the  microscope  were  reflected 
directly  upon  the  steel  plate,  and  drawn  with  the  needle.  They  are, 
therefore,  as  nearly  as  possible,  correct  in  dimension  and  detail.  The 
pictures  are  two  sections  of  the  vein  from  the  right  foot,  and  the 
parts  represented  were  separated  by  less  than  a  quarter  of  an  inch. 
Both  views  show  the  vessel  to  be  almost  closed.  The  vein  appears  as 
a  nearly  solid  cord,  instead  of  being  a  thin-walled  tube,  as  natural 
veins  are.  The  material  filling  the  calibre  is  represented  in  the  two 
pictures  as  being  very  different.  In  Fig.  34  there  is  a  good  deal  of 
thickening  of  the  intima,  but  much  the  greater  part  of  the  thickened 
tissue  is  the  muscular  coat,  outside  of  which  is  the  adventitia,  which 
presents  no  evidence  of  disease.  The  intima  is  composed  of  fibrous 
tissue,  in  which  the  nuclei  are  easily  distinguished,  and  the  small  slit- 
shaped  opening  is  lined  by  a  fringe  of  endothelial  nuclei.  Such  an 
appearance  of  the  intima  and  of  the  calibre  is  common  in  diseased 
arteries.  The  muscularis,  on  the  other  hand,  which  occupies  quite 
two-thirds  of  the  entire  thickness  of  the  vessel  wall,  is  unlike  anything 
that  I  have  previously  seen  in  diseased  blood-vessels.  Although  it  is 
correct  to  call  it  the  muscular  coat,  by  no  means  all  of  it  is  muscular 
tissue.  The  muscle  fibres,  with  their  long,  narrow  nuclei,  are  well 
represented  in  the  drawing  ;  but  it  is  also  seen  that  the  bands  have 
been  separated  and  thrown  into  wavy  lines  by  a  material  which  has 
grown  in  the  midst  of  the  muscular  tissue,  and  has  distorted  it.  This 
tissue  is  represented  by  the  lighter  colored  areas  in  the  picture,  and 
they  also  contain  many  nuclei,  but  these  are  different  in  appearance 
from  the  muscular  nuclei.  Evidently  a  morbid  fibroid  tissue  has 
grown  in  the  muscularis,  and  at  its  expense.  The  appearances  here 
represented  are  a  more  graphic  demonstration  than  anything  I  have 
previously  met  that  it  is  an  error  to  call  this  increase  of  thickness  of 
the  muscular  coat  a  hypertrophy,  as  is  commonly  said  of  it  when  it 
occurs  in  arteries,  and  that  it  is  unreasonable  to  believe  it  can  add  to 
the  power  of  useful  contractility  of  vessels.  Fig.  35  is  very  different 


56  HUMAN  BLOOD-VESSELS 

from  Fig.  34,  but  a  careful  examination  of  it  reveals  that  the  disease 
which  distorted  the  two  parts  of  the  vein  had  worked  in  a  somewhat 
similar  manner  in  both  parts.  The  most  striking  characteristic  is  the 
large  knots  of  twisted  tissue  which  fill  up  a  great  part  of  the  calibre  of 
the  vein.  These  masses  resemble  the  knots  that  are  formed  by  a  large 
number  of  earthworms  together,  and  they  are  the  result  of  a  growth  of 
the  intima  which  was  so  rapid  as  to  outstrip  the  growth  of  other  parts 
of  the  vein,  so  that  the  calibre  could  contain  them  only  when  coiled 
and  twisted. 

"  There  are  parts  of  the  calibre  where  the  intima  is  moderately  thick- 
ened and  the  endothelial  cells  are  distinct  in  places,  but  they  are  gener- 
ally somewhat  enlarged  and  more  rounded  than  is  natural,  and  few,  if 
any,  of  them  appear  as  flat  plates  upon  the  inner  side  of  the  vessel. 
There  is  great  thickening  of  the  muscular  coat,  but  this  is  less  in  degree 
than  that  represented  by  Fig.  34 ;  and  in  places  the  muscularis  and 
intima  run  together  in  such  a  way  that  it  is  impossible  to  say  where 
the  one  ends  and  the  other  begins.  The  disease  has  gone  so  far  that  the 
muscular  tissue  bears  little  resemblance  to  natural  muscle,  and  the  intima 
as  little  to  the  natural  intima  of  veins.  Disease  often  totally  changes  the 
appearance  of  tissues,  and  this  reminds  one  that  at  early  embryological 
stages  the  various  organs  are  so  much  alike  that  they  can  be  recognized 
with  the  microscope  only  by  their  situations,  and  not  by  the  arrange- 
ment or  appearance  of  their  cells.  It  seems  as  if  disease  is  sometimes 
of  the  nature  of  a  retrogression.  The  diseased  tissues  lose  their  nat- 
ural characteristics,  and  fall  back  toward  the  lack  of  differentiation 
which  is  natural  in  the  tissues  of  early  embryos.  The  cause  which 
seems  to  have  the  greatest  influence  in  bringing  about  this  retrogres- 
sion is  the  growth  of  morbid  fibroid  tissue.  In  the  forms  of  disease 
represented  by  the  two  pictures,  the  most  striking  feature  in  both  is 
the  growth  of  morbid  fibroid  tissue  in  the  intima  and  in  the  muscularis. 

"The  disease  that  has  been  described,  and  which  is  shown  by  the 
pictures,  would  be  attributed  by  most  persons  to  syphilis,  as  the 
patient  said  he  had  been  infected,  and  this  explanation  would  gener- 
ally be  considered  to  be  satisfactory  and  conclusive.  It  may  be 
that  the  disease  was  syphilis,  and  there  is  no  other  cause  at  hand 
which  better  explains  the  disease  of  the  vein,  the  extensive  endar- 
teritis,  and  the  disease  of  the  heart  which  the  physical  examination 
of  the  patient  demonstrated.  There  is  good  reason  for  believing  that 


DISEASE  OF  VEINS  57 

syphilis  produces  such  vascular  disease,  but  it  would  be  a  mistake  to 
suppose  that  syphilis  only  can  cause  it."  I  know  that  syphilis  is  not 
always  the  cause  of  the  disease,  for  I  have  seen  it  in  patients  who  were 
not  syphilitic  but  who  died  from  other  causes.  For  example,  Fig.  36 
is  one  of  the  radial  veins  of  a  negro  woman  twenty-seven  years  old, 
who  died  of  typhoid  fever.  The  disease  is  similar  to  that  shown  by 
both  Figs.  34  and  35,  for  in  addition  to  the  exuberant  growth  of  the 
intima,  making  it  resemble  earthworms,  the  muscularis  is  very  much 
thickened  and  its  tissue  is  torn  apart  and  destroyed  by  the  fibrous 
tissue  which  has  grown  among  the  muscular  fibres.  Fig.  37  is  a 
section  of  the  same  vein  as  Fig.  36,  and  the  section  is  from  a  portion 
of  the  vein  very  near  that  shown  by  Fig.  36.  The  character  of  disease, 
however,  is  quite  different.  The  calibre  is  small  but  not  nearly  oblit- 
erated, and  the  wall  is  thick.  A  great  part  of  the  wall  is  formed  of 
the  muscularis,  which  is  fibroid  and  has  its  muscular  fibres  torn  apart 
so  that  it  presents  an  open-meshed  appearance.  These  two  sections 
(Figs.  36  and  37)  demonstrate  in  a  striking  way  how  the  character  of 
disease  of  blood-vessels  varies  at  different  parts  of  the  same  vessel  and 
even  of  parts  lying  very  close  together.  Another  example  of  a  vein 
with  its  calibre  obstructed  by  proliferation  of  the  intima  is  afforded 
by  Fig.  49,  which  will  presently  be  described.  It  was  taken  from  a 
boy  who  died  of  meningitis  and  who  certainly  was  not  syphilitic. 

It  is  not  uncommon  to  find  the  muscular  coat  of  the  radial  veins 
thickened  and  the  fibres  separated  by  the  growth  of  morbid  fibroid 
tissue  in  persons  whose  radial  vessels  had  been  felt  during  life  to  be 
thickened.  In  my  book  on  the  "Origin  of  Disease"1  there  is  a 
picture  of  a  portion  of  the  vena  cava  of  a  man  fifty-seven  years  old, 
who  died  of  Bright's  disease,  which  shows  thickening  of  the  muscu- 
lar wall  and  separation  of  its  fibres.  As  it  has  now  been  shown  that 
these  changes  of  the  veins  occur  in  persons  suffering  with  other  dis- 
eases, and  who  were  not  syphilitic,  it  would  be  an  error  to  emphasize 
too  much  the  fact  that  the  patient  from  whom  the  vein  represented 
by  Figs.  34  and  35  was  taken  had  been  infected  with  syphilis.  It  is 
now  well  known  that  the  form  of  endarteritis  which  used  to  be  con- 
sidered syphilitic  arises  also  from  a  variety  of  other  causes,  and  the 
appearances  of  the  veins  from  which  the  illustrations  were  made 

1  The  Origin  of  Disease,  by  Arthur  V.  Meigs,  page  59  and  Fig.  36. 


58  HUMAN  BLOOD-VESSELS 

demonstrate  that  endophlebitis  is  due  to  other  causes  besides  syphilis. 
It  is  singular  how  a  part  of  a  vein  may  be  excessively  diseased  and 
another  portion  very  near  may  be  quite  differently  diseased  ;  this  has 
been  shown  by  Figs.  36  and  37.  Fig.  38  presents  a  condition  in 
some  respects  parallel  but  in  others  very  different.  It  shows  the  same 
superficial  vein  of  the  skin  of  the  foot  as  Figs.  34  and  35,  but  the  sec- 
tion was  so  cut  as  to  include  one  of  the  branches  that  ran  along  the 
sides  of  the  toes.  The  main  vein  presents  the  same  character  of  dis- 
ease as  that  shown  by  Fig.  34,  and  which  has  already  been  described, 
but  the  branch  offers  a  striking  contrast.  It  is  thin-walled  and  does 
not  appear  to  be  diseased,  and,  what  is  perhaps  more  striking  still, 
structurally  it  is  not  a  vein  at  all,  but  is  a  capillary.  The  transition 
from  the  vein,  with  walls  so  thick  that  its  calibre  is  almost  obliterated, 
to  the  thin-walled  capillary  which  seems  to  be  normal,  is  quite  sudden. 
It  seems  as  if  nature  had  broken  her  rule,  which  is,  that,  almost  with- 
out exception,  she  draws  no  hard  lines  and  does  nothing  abruptly. 
The  question  suggests  itself — and  it  is  one  of  interest — whether  it  can 
be  that  many  of  the  small  superficial  cutaneous  veins  which  are  easily 
seen  with  the  unaided  eye  may  be  really  capillaries  and  not  veins  at 
all.  The  veins  at  the  sides  of  the  toes  are  often  easy  to  see,  and  they 
are  filled  with  blue  blood  like  other  veins,  but  the  vessel  (c,  Fig.  38) 
shown  by  the  illustration  has  not  three  coats  and  it  is  composed  of 
endothelium  alone. 

Figs.  39,  40,  and  41  are  three  arteries  with  their  accompanying 
veins.  The  arteries,  although  quite  unlike  the  accepted  standards  of 
the  normal,  show  nothing  unusual  ;  but  the  veins  are  diseased,  and 
they  are  in  some  respects  affected  alike  and  in  others  differently.  All 
of  them  are  thick-walled,  but  the  nature  of  the  tissue  composing  the 
walls  is  different.  They  are  from  persons  of  very  different  ages  and 
who  died  of  different  and  unrelated  diseases.  Fig.  39  is  from  the 
mesentery  of  a  negro  infant  one  year  old  that  died,  after  an  illness 
lasting  six  months,  of  chronic  catarrhal  pneumonia  following  whooping- 
cough.  The  artery  is  thick-walled,  but  presents  no  other  point  of 
interest.  The  vein  also  has  thick  walls,  and  it  shows  fibroid  disease  of 
the  muscularis  of  the  same  character  as  that  shown  by  Fig.  34  and 
the  other  veins  described  in  connection  with  it.  Fig.  40  shows  an 
artery  and  a  vein  from  a  negro  woman  twenty-seven  years  old,  who 
died  of  tubercular  meningitis  and  pulmonary  tuberculosis  and  ulcer 


FIG.  36. — FIBROID  VEIN.     (X  50.) 

From  the  same  case  as  Figs.  29,  37,  and  42.  A  radial  vein.  The  wall  of  the  vein  is 
greatly  thickened.  A  great  part  of  the  thickening  is  of  the  muscular  coat,  which  is  of  loose 
texture,  like  other  diseased  veins  that  are  represented  by  the  illustrations.  Morbid  fibroid 
tissue  was  deposited  in  the  muscularis.  The  lumen  is  almost  filled  by  threads  like  earth- 
worms, which  are  attached  to  the  lining  of  the  vein.  It  is  as  if  the  intima  had  grown  very 
voluminous  and  then  been  cast  loose  from  its  attachment.  Fig.  37  depicts  a  section  cut  from 
the  same  vein  and  close  to  the  part  shown  by  Fig.  36.  The  muscularis  is  similarly  diseased 
in  both  sections,  but  there  are  no  loose  shreds  in  the  lumen  in  Fig.  37. 

FIG.  37. — FIBROID  VEIN.     (X  50.) 

From  the  same  case  as  Figs.  29,  36,  and  42.  A  section  of  the  same  vein  that  is  repre- 
sented by  Fig.  36  and  cut  close  by  the  other  section.  It  exhibits  similar  thickening  of  the 
wall  and  the  same  diseased  loose-textured  state  of  the  muscular  tissue,  but  there  are  no  loose 
shreds  from  the  lining  hanging  in  the  lumen. 


FIG.  36. 


FIG.  37. 


FIG.  38. — DISEASED  VEIN  WITH  CAPILLARY  BRANCH.     (X  50.) 

From  the  same  case  as  Figs.  34  and  35.  The  same  vein,  with  a  portion  of  one  of  its 
branches  (c )  that  ran  at  the  sides  of  the  toes.  The  vein  shows  the  same  disease  of  the 
three  coats  as  Fig.  34.  The  branch,  however,  which  was  large  enough  to  be  easily  seen  with 
the  naked  eye  before  it  was  removed  from  the  foot,  presents  the  appearances  of  a  capillary. 
The  most  striking  characteristic  is  the  sudden  transition  from  disease  to  the  normal.  The 
vein  is  thick,  so  that  its  lumen  is  almost  closed,  and  this  was  perceived  during  life,  while  the 
branch  is  thin  and  seems  quite  normal. 


FIG.  38. 


DISEASE  OF  VEINS  59 

of  the  stomach.  The  artery  and  vein  are  from  a  portion  of  the 
stomach  close  to  the  ulcer.  The  artery  might  almost  be  regarded  as 
a  type  of  the  normal  of  blood-vessels  of  its  size.  The  vein  is  thick- 
walled  from  fibroid  overgrowth  of  precisely  similar  character  to  that 
represented  by  Fig.  31.  The  fibroid  disease  shown  by  Figs.  31  and 
34  and  by  Figs.  39  and  40  is  of  the  same  general  character,  for 
in  all  four  of  them  the  principal  lesion  that  can  be  recognized  is 
the  excessive  growth  of  fibroid  tissue  in  places  where  under  natural 
conditions  there  is  very  little  of  it.  As  seen  in  Figs.  3 1  and  40  the 
muscular  tissue  is  so  torn  apart,  and  there  are  so  many  openings 
through  the  muscular  layers  to  the  adventitia  outside,  as  to  suggest 
that  the  fibroid  disease  had  its  origin  in  the  adventitia,  or  entirely  out- 
side the  vessels  in  the  perivascular  connective  tissue,  and  that  the 
fibrous  tissue  forced  its  way  into  them  just  as  growing  cancer  pene- 
trates adjacent  tissues.  This  parallel  was  suggested  and  is  discussed 
at  page  5  i .  The  fact  that  exactly  the  same  sort  of  lesions  may  be 
found  to  result  in  the  veins  of  persons  dying  of  such  different  diseases 
as  tuberculosis  and  chronic  pulmonary  inflammation,  and  at  such 
different  ages  as  twenty-five  years  and  one  year,  is  both  striking  and 
curious. 

Fig.  41  is  a  drawing  of  an  artery  and  a  vein  of  the  colon  of  a 
woman  twenty-six  years  old  who  died  of  typhoid  fever.  The  artery 
is  thick-walled,  but  it  presents  no  points  of  special  interest  nor  any- 
thing worthy  of  discussion  here.  It  was  included  merely  to  set  off  the 
vein  and  to  give  a  more  graphic  and  complete  representation.  The 
vein  is  even  thicker-walled  than  the  artery,  and  the  tissue  composing 
the  wall  is  of  a  very  different  character  from  that  of  the  veins  shown  by 
Figs.  39  and  40.  The  tissue  does  not  look  like  involuntary  muscle,  of 
which  the  greater  part  of  the  walls  of  the  veins  depicted  in  Figs.  39 
and  40  is  formed.  If  there  is  any  muscular  tissue  in  the  wall  of  Fig. 
41  it  has  been  so  much  changed  by  disease  that  it  is  no  longer 
recognizable.  There  are  very  few  fibres  extending  circularly  around 
the  vein,  as  there  are  in  Figs.  39  and  40,  and  none  of  the  long,  narrow 
nuclei  which  are  ordinarily  the  most  prominent  characteristics  of  the 
muscularis  of  blood-vessels.  On  the  contrary,  the  nuclei  are  large 
and  are  nearly  round.  This  state  of  disease  of  the  vein — the  thicken- 
ing of  the  wall,  the  swollen  and  rounded  character  of  the  nuclei,  and 
the  absence  of  the  circular  fibres — is  to  be  attributed  to  the  acute 


6o  HUMAN  BLOOD-VESSELS 

inflammatory  disease  of  which  the  patient  died.  Typhoid  fever  lasts 
but  a  few  weeks,  and  it  is  probable  that  up  to  the  time  of  the  onset  of 
the  fatal  attack  the  blood-vessels  of  the  patient  were  normal.  The 
appearance  of  the  vein  Fig.  41  stands  in  marked  contrast  to  that  of  the 
veins  Figs.  39  and  40,  which  were  taken,  as  has  already  been  said,  from 
patients  who  died  of  chronic  diseases. 

Fig.  42  represents  a  blood-vessel  of  a  negro  woman  twenty-seven 
years  old  who  died  of  typhoid  fever.  The  drawing  was  made  from 
a  section  of  the  radial  artery,  its  accompanying  blood-vessels,  and 
surrounding  tissue.  From  its  situation  and  appearance  I  believe  the 
vessel  to  be  a  minute  vein,  but  it  is  so  entirely  unlike  any  normal 
blood-vessel  that  it  is  impossible  to  be  certain  that  it  is  not  an  arteriole 
or  a  capillary.  Its  cell  structure  is  more  like  epithelium  than  like  any 
of  the  other  human  tissues,  and  there  is  nothing  that  in  the  least 
resembles  the  intima,  the  muscularis,  or  the  adventitia  of  normal  blood- 
vessels. In  my  book  on  "The  Origin  of  Disease,"  1  I  described  a 
blood-vessel  which  in  many  respects  resembles  Fig.  42.  That  vessel 
is  from  the  thickened  mucosa  of  the  colon  of  a  man  who  died  of  acute 
dysentery,  and  I  took  it  to  be  an  arteriole;  but,  as  in  the  case  of 
Fig.  42,  it  is  impossible  to  be  sure  whether  the  vessel  is  an  artery,  a 
vein,  or  a  capillary.  They  are  both  entirely  unlike  normal  blood- 
vessels, and  the  tissue  that  composes  them  is  more  like  epithelium  than 
like  any  other  normal  tissue.  It  is  strange  how  disease  can  change 
the  normal  tissues  so  much  as  to  render  them  unrecognizable.  What 
produces  such  a  condition  as  this  I  am  entirely  unable  to  say,  and  it 
would  be  quite  useless  to  indulge  in  conjecture  when  there  are  no 
facts  upon  which  to  base  an  opinion. 

My  description  of  disease  of  the  veins  is  imperfect.  It  was  not  my 
purpose,  however,  to  write  a  complete  account  of  all  that  is  known  of 
the  subject,  but  to  describe  what  I  have  myself  seen.  It  has  been 
impossible  to  classify  disease  of  the  veins  in  a  satisfactory  manner,  for 
there  is  not  enough  known  ot  the  subject  even  for  the  foundation  of 
a  classification. 

1  Page  50  and  Fig.  16. 


FIG.  39. — THICKENED  ARTERY  AND  DISEASED  VEIN  OF  THE  MESENTERY.     (X  105.) 

From  a  negro  infant  one  year  old  that  died  of  chronic  catarrhal  pneumonia.  The  lower 
flattened  vessel  is  an  artery,  of  which  the  muscular  coat  is  somewhat  thick, — a  very  common 
change  in  chronic  disease.  The  vein,  which  is  above,  is  very  thick-walled,  and  the  nature  of 
the  tissue  is  similar  to  that  shown  by  Fig.  34. 

FIG.  40. — ARTERY  AND  DISEASED  VEIN  FROM  STOMACH.     (X  50.) 

From  a  negro  woman  twenty-five  years  old  who  died  of  tubercular  meningitis  and  pul- 
monary tuberculosis  and  ulcer  of  the  stomach.  The  vessels  lie  close  to  the  ulcer.  The 
artery,  which  is  above,  is  of  normal  appearance.  The  vein,  which  is  below,  has  greatly  thick- 
ened walls.  The  tissue  is  of  the  same  nature  as  that  shown  by  Fig.  34.  There  is  muscular 
tissue  which  is  torn  apart  by  fibrocellular  material  which  has  grown  in  it,  and  the  intima  is 
more  thickened  than  is  usual  in  veins. 


FIG.  41. — ARTERY  AND  DISEASED  VEIN  OF  THE  COLON.     (X  105.) 

From  a  woman  twenty-six  years  old  who  died  of  typhoid  fever.  The  vessel  above  is  the 
artery  and  that  below  the  vein.  The  artery  is  perhaps  a  little  thickened.  The  vein  is  much 
diseased,  being  thick-walled  and  composed  of  tissue  quite  unlike  that  of  normal  veins.  This 
tissue  is  somewhat  like  that  shown  by  Fig.  34,  but  the  nuclei  are  round  or  rounded.  It  does 
not  look  like  muscular  tissue. 


FIG.  39. 


FIG.  40. 


FIG.  41. 


FIG.  42. — BLOOD-VESSEL  OF  ATYPICAL  UNUSUAL  STRUCTURE.     (X  240.) 

From  a  negro  woman  twenty-seven  years  old  who  died  of  typhoid  fever.  A  blood-vessel 
lying  near  the  right  radial  artery.  Figs.  29,  36,  and  37  are  from  the  same  patient.  There 
is  a  strong  general  resemblance  to  a  tiled  pavement.  The  tissue  is  more  like  epithelium  than 
like  that  of  ordinary  arteries,  veins,  or  capillaries,  and  it  is  impossible  to  know  to  which  class 
it  belongs. 


FIG.  42. 


CHAPTER     VI 

DISEASE  OF  THE  RADIAL  ARTERIES  AND  VEINS 

DISEASE  of  the  radial  artery  is  often  recognized  during  life  because 
the  custom  of  feeling  the  pulse  at  the  wrist  directs  the  attention  of 
physicians  to  its  condition  more  than  to  that  of  any  other  blood- 
vessel. The  radial  artery  can  frequently  be  felt  to  be  thickened,  and 
be  seen  to  pulsate.  Any  great  thickening  of  it  is  always  morbid,  and 
constant  excessive  visible  pulsation  indicates  the  existence  of  disease 
of  the  heart,  or  of  the  vessel  itself,  or  of  both.  Evidence  of  disease 
obtained  by  feeling  the  pulse  has  heretofore  usually  been  thought  to 
denote  disease  of  the  heart  unless  it  was  considered  that  the  artery 
itself  was  diseased,  and  very  little  attention  has  been  paid  to  the  state 
of  the  veins.  My  own  experience  has  shown  me  that  disease  attacks 
the  veins  about  as  frequently  as  the  arteries,  and  that  it  is  very  com- 
mon for  them  both  to  be  affected.  There  is  even  less  known  of  the 
effects  of  disease  of  the  veins  than  of  those  of  the  arteries,  and  almost 
nothing  is  known  of  clinical  symptoms  which  may  result  directly 
from  disease  of  the  veins  or  arteries.  Disease  of  the  radial  blood- 
vessels found  in  feeling  the  pulse  is  generally  due  to  fibroid  degener- 
ation, which  is  the  curious  process  that  I  have  said  is  inevitable  to  the 
advance  of  years  and  is  not  rare  in  the  young.  When  disease  of  the 
radial  artery  has  been  recognized  during  life,  it  is  often  possible  to 
be  almost  certain  that  disease  of  other  blood-vessels  also  exists.  The 
exact  effects  of  these  physical  changes  of  the  blood-vessels  are  as  yet 
unknown.  It  is,  however,  well  known — and  the  fact  should  be  kept 
constantly  in  mind  by  physicians — that  extensive  disease  of  the  blood- 
vessels may  exist,  especially  in  old  people,  and  yet  good  general 
health  be  maintained  for  long  periods. 

Fig.  43  shows  the  right  radial  artery  and  veins  from  a  negro  man 
nineteen  years  old  who  died  of  typhoid  fever.  Fig.  44  represents 
the  left  radial  artery  and  one  vein  from  the  same  patient.  Generally 
there  are  two  veins  accompanying  the  radial  artery,  and  probably  the 
reason  why  only  one  is  to  be  seen  in  Fig.  44  is  that  the  second  was 
overlooked  and  left  behind  when  the  piece  of  tissue  was  dissected 
from  the  wrist.  The  contrast  presented  by  these  two  sets  of  radial 

61 


62  HUMAN  BLOOD-VESSELS 

arteries  and  veins  is  very  striking.  The  vessels  depicted  by  Fig. 
44  may  be  taken  as  almost  typically  normal,  and  if  they  are  com- 
pared with  those  of  Fig.  1 3,  which  I  have  described  as  normal,  it  will 
be  seen  that  the  two  sets  of  vessels  are  very  nearly  alike.  .  The  mus- 
cularis  of  the  artery  (Fig.  44)  is  of  irregular  thickness  at  different  parts 
of  its  circumference,  and  it  is  probably  a  little  thicker  than  normal. 
I  do  not  think  the  intima  can  be  said  to  be  diseased,  for  it  is  not  usual 
to  find  it  any  thinner  in  the  radial  artery.  The  vein  is  very  similar 
in  appearance  to  the  one  shown  by  Fig.  13.  The  accepted  standard 
of  the  normal  appearance  of  veins  seems  certainly  to  be  incorrect 
as  far  as  concerns  the  radial  vein  at  least.  The  common  conception 
of  veins  is  that  they  are  a  good  deal  like  the  arteries,  being  composed 
of  three  tunics,  and  that  the  tissue  forming  these  three  tunics  is  of 
similar  nature  to  that  of  arteries.  It  is  supposed  that  the  differences 
of  the  two  kinds  of  vessels  one  from  another  are  that  the  tunics  are 
of  different  degrees  of  thickness  and  that  the  amount  of  elastic  tissue 
is  different.  Veins  such  as  are  shown  by  Figs.  44  and  1 3  differ  from 
arteries  much  more  widely  than  ordinary  descriptions  and  the  illustra- 
tions in  most  text-books  represent  Fig.  43  presents  a  very  different 
state  of  things  from  Fig.  44.  The  artery  is  thick- walled  and  the  thick- 
ening is  irregular  in  its  distribution.  The  intima  cannot  be  said  to  be 
abnormal ;  it  has  very  much  the  same  character  as  that  of  the  artery  in 
Fig.  44.  The  adventitia  also  appears  to  be  normal,  but  the  muscularis 
is  the  diseased  tunic.  The  irregularity  of  thickness  of  the  vessel  at 
different  parts  is  confined  entirely  to  the  muscularis,  which  by  meas- 
urement is  twice  as  thick  to  the  right  as  it  is  to  the  left  in  the 
drawing.  If  the  vessel  be  studied  with  greater  amplification  than  was 
used  to  make  the  illustration,  it  is  seen  that  the  tissue  is  diseased. 
There  is  not  simply  an  increase  of  the  muscular  tissue,  constituting  a 
hypertrophy  which  might  have  endowed  the  vessel  with  an  added, 
power  to  perform  its  function,  but  it  is  seen  that  there  is  hyperplasia 
which  is  due  to  degeneration.  The  veins  shown  by  Fig.  43  are  also 
very  different  from  the  one  shown  by  Fig.  44.  The  muscular  tissue 
which  composes  the  greatest  part  of  the  walls  of  the  veins  in  Fig.  43 
is  loose  meshed,  like  that  shown  by  Fig.  34  and  in  the  vein  directly 
above  and  to  the  right  of  the  artery,  and  in  this  vein  the  intima  is 
proliferated  and  hangs  loose  in  the  lumen  in  the  same  way  as  that 
shown  by  Fig.  35.  The  extent  of  this  peculiar  disease  is  not  great  in 


FIG.  43. — DISEASED  RADIAL  ARTERY  AND  VEINS.      (X  20.) 

The  right  radial  artery  and  veins  from  a  negro  man  of  nineteen  years  who  died  of  typhoid 
fever.  The  artery  is  thick-walled,  the  thickening  being  nearly  twice  as  great  upon  one  side 
as  on  the  other.  Both  the  intima  and  the  muscularis  are  thicker  than  is  generally  represented 
as  natural.  The  veins  are  not  natural,  being  slightly  thick- walled,  and  the  muscular  tissue 
presents  to  a  slight  extent  the  loose-meshed  appearance  that  is  common  in  diseased  veins. 
There  are  shreds  which  hang  from  the  lining  lying  in  the  lumen  of  the  small  vein  above  and 
to  the  right  of  the  artery.  These  diseased  vessels  present  a  strong  contrast  to  the  left  radial 
artery  and  vein  of  the  same  patient,  which  are  represented  by  Fig.  44. 


FIG.  44. — NEARLY  NORMAL  RADIAL  ARTERY  AND  VEIN.      (X  20.) 

The  left  radial  artery  and  vein  from  the  same  man  as  the  vessels  represented  by  Fig.  43. 
The  artery  is  to  the  right  and  the  vein  to  the  left.  The  two  blood-vessels  are  but  slightly 
abnormal,  as  may  be  recognized  by  comparing  them  with  Fig.  13.  The  contrast  with  Fig. 
43  is  very  striking. 


FIG.  43. 


FIG.  44. 


DISEASE  OF  THE  RADIAL  ARTERIES  AND  VEINS          63 

the  present  case,  for  the  calibre  of  the  vein  is  not  nearly  filled  and  it       / 
contains  quite  a  mass  of  red  blood-corpuscles  ;  but  if  the  vessel  is  exam- 
ined with  greater  amplification  the  disease  can  be  seen  to  be  of  exactly 
the  same  character  as  that  shown  by  Fig.  35,  though  it  has  not  pro- 
gressed so  far.     The  most  striking  feature,  however,  of  Figs.  43  and     I 
44,  which,  as  has  been  said,  are  the  right  and  left  radial  arteries   and    / 
veins  from  the  same  patient,  is  that  the  one  set  of  blood-vessels  is  so   / 
much  diseased  and  the  other  is  practically  normal.      It  is  impossible  / 


to  comprehend  why  two  sets  of  blood-vessels  that  were  probably  ex- 
posed to  the  same  influences  to  cause  disease  of  them  or  to  leave  them 
healthy  should  be  so  totally  different. 

Another  interesting  point  is  the  discovery,  in  a  young  man  of  nine- 
teen years  who  died  of  typhoid  fever  (which  is  an  acute  disease  that 
runs  its  course  in  a  few  weeks),  of  such  a  diseased  artery  as  that  shown 
by  Fig.  43.  The  thickening  of  the  muscularis,  which  I  believe  to  have 
been  the  result  of  morbid  fibrosis,  was  probably  of  slow  growth  and 
very  likely  it  existed  for  a  good  while  before  the  acute  fatal  attack. 
If  such  was  the  case  the  patient  suffered  with  chronic  latent  disease 
which  gradually  undermined  his  health  for  some  time  before  the  out- 
break of  the  acute  attack  which  ended  fatally.  Fibroid  disease  of 
the  blood-vessels,  which  is  usually  regarded  rather  as  a  disease  of  per- 
sons of  advanced  years,  is  striking  when  it  occurs  at  nineteen  years 
of  age.  In  my  book  on  the  "Origin  of  Disease"  I  have  discussed  this 
curious  latency  of  chronic  fibrosis,  and  have  shown  that  a  careful 
examination  of  the  bodies  of  those  dead  of  acute  disease  often  reveals 
the  presence  of  lesions  of  chronic  nature  which  must  have  long 
antedated  the  acute  fatal  attack,  and  may  very  probably  have  played 
an  important  part  in  rendering  the  individual  liable  to  the  acute 
disease. 

Figs.  45  and  46  represent  two  sections  of  the  same  radial  artery 
and  veins  of  a  negro  man  twenty-four  years  old  who  died  of  tuber- 
culosis. The  sections  are  of  parts  of  the  vessels  that  were  not  more 
than  a  quarter  of  an  inch  apart.  It  is  strange  that  two  portions  of  the 
same  vessels  separated  by  such  a  slight  distance  should  be  so  different. 
As  shown  by  Fig.  46,  the  artery  is  nearly  round  and  its  wall  is  a  good 
deal  thicker  than  in  Fig.  45,  which  is  of  irregular  shape.  Part  of  this 
difference  may  be  due  to  greater  shrinkage  of  the  artery  shown  by 
Fig.  46  ;  but,  as  the  two  pieces  of  tissue  from  which  the  sections  were 


i 


64  HUMAN  BLOOD-VESSELS 

cut  were  subjected  to  the  action  of  the  same  reagents,  it  is  unlikely 
that  the  difference  is  wholly  due  to  the  mode  of  preparation  ;  it  is 
much  more  probable  that  it  is  the  result  of  disease.  Besides,  it  was 
ascertained  during  the  life  of  the  patient,  by  feeling  the  pulse  at 
the  wrist,  that  the  radial  vessels  were  thickened.  The  muscularis  of 
the  arteries  is  thick  in  both  of  the  sections,  and  the  cause  of  this 
thickness  is  degeneration,  not  hypertrophy.  The  intima  also  is  un- 
naturally thick,  as  may  be  recognized  by  comparing  it  with  Fig.  13, 
which  is  normal.  The  veins  are  even  more  evidently  diseased  than 
the  arteries.  It  is  impossible  to  be  sure  that  all  the  vessels  sur- 
rounding these  two  sections  of  the  radial  artery  are  veins,  although 
some  of  them  can  be  recognized  with  certainty.  The  two  minute 
vessels,  a  and  c,  Fig.  45,  are  entirely  closed  by  plugs  of  tissue.  They 
are  probably  veins,  but  they  are  so  much  changed  by  disease  that  it 
cannot  be  said  that  they  may  not  be  arterioles.  Examination  of 
these  two  blood-vessels  with  greater  amplification  demonstrates  that 
the  plugs  in  the  calibres  are  not  mere  blood-clots,  but  are  formed  of 
well-organized  fibrous  tissue.  It  is  not  rare  for  blood-vessels  to  be- 
come thus  occluded,  and  the  tissue  that  grows  in  the  lumen  may  be 
well  organized  and  may  contain  a  vascular  supply  of  its  own.  Such  a 
vessel  is  shown  and  described  in  my  book  on  the  "  Origin  of  Disease  " 
(page  45  and  Fig.  13).  Two  of  the  veins,  b  and  d,  Fig.  45,  are  thick- 
walled,  and  the  tissue  forming  the  walls  is  almost  entirely  muscular. 
This  muscular  tissue  is  loose  meshed  and  torn  apart  by  the  growth  of 
fibrous  tissue  between  the  threads  of  muscle,  and  in  one  of  the  veins 
there  is  slight  proliferation  of  the  intima  and  a  loose  shred  hangs  in  the 
lumen.  The  disease  is  evidently  an  early  stage  of  the  same  process  that 
is  shown  by  Figs.  34  and  35.  The  veins  in  Fig.  46  are  even  more  ex- 
tensively diseased  than  those  in  Fig.  45,  all  of  them  being  thick-walled 
and  the  walls  formed  almost  entirely  of  muscular  tissue  which  is  open 
meshed,  owing  to  fibroid  disease.  One  of  the  veins  (e)  is  nearly 
closed.  There  are  loose  strands  of  the  overgrown  intima  hanging  in 
the  lumen  and  a  fan-shaped  mass  which  seems  to  be  composed  of 
muscular  tissue  which  has  undergone  fibroid  degeneration.  This  ob- 
struction of  the  veins  is  a  very  curious  form  of  disease,  and  it  is 
evident  that  it  is  not  uncommon. 

Figs.  47,  48,  49,  and  50  show  the  radial  artery  and  veins  of  a  boy 
fifteen  years  old  who  died  of  acute   meningitis.       It  was  perceived 


FIG.  45. — THICKENED  RADIAL  ARTERY  AND  DISEASED  VEINS.     (X  20.) 

From  a  negro  man  twenty-four  years  old  who  died  of  tuberculosis.  The  artery  is  the 
large  vessel  in  the  centre.  Its  three  coats  and  the  plicated  membrane  are  easily  distinguished. 
The  intima  and  muscularis  are  thicker  than  natural,  and  the  plicated  membrane  more  folded 
than  usual,  a,  a  vein  entirely  closed  by  a  plug  of  organized  tissue,  b,  a  vein  with  thick  and 
diseased  walls  (of  somewhat  the  same  nature  as  Fig.  34)  and  strings  from  the  lining  hanging 
in  the  lumen,  c,  a  small  vein  in  which,  when  more  highly  magnified,  the  plicated  mem- 
brane can  be  seen,  and  with  the  lumen  entirely  closed  by  an  organized  plug  of  tissue.  The 
vein  is  a"  solid  rod.  (/,  a  vein  with  thickened  walls  composed  of  loose-meshed,  diseased 
muscle.  None  of  these  veins  have  walls  in  the  least  like  natural  walls  of  veins. 


FIG.  45. 


Fro.  46. — THICKENED  RADIAL  ARTERY  AND  DISEASED  VEINS.     (X  20.) 

The  same  artery  and  its  surrounding  veins  as  are  shown  by  Fig.  45.  The  general  char- 
acteristics are  very  similar.  The  walls  of  the  artery  are  thicker,  the  plicated  membrane  is 
even  more  folded,  and  the  calibre  is  smaller.  It  may  be  more  shrunken  than  the  other  sec- 
tion, although  they  were  cut  less  than  a  quarter  of  an  inch  apart,  e,  a  vein  with  thick  walls 
and  with  twisted  strands  of  tissue  from  the  lining  resembling  a  fan  in  the  lumen,  y'and^  are 
veins  with  thickened  walls  which  are  composed  entirely  of  loose-meshed,  diseased  muscular 
tissue. 


FIG.  46. 


Taf^^Hjfn^f^J^'.f    '  £      '^f**,  ^ 

'    X ..  ,\trtf\.  *v.      * 


FIG.  47.— DISEASED  RADIAL  ARTERY  AND  VEINS.     (X  20.) 

From  a  boy  fifteen  years  old  who  died  of  acute  meningitis.  The  artery,  which  is  the 
largest  vessel,  is  thick-walled,  the  muscularis  especially  being  thick,  h  is  a  region  repre- 
sented more  highly  magnified  by  Fig.  48.  e,  f,  and  g  are  veins  and  they  are  all  diseased. 
Their  walls  are  formed  of  tissue  like  that  of  the  muscularis  of  Fig.  34.  c  is  thick-walled  and 
is  very  like^  except  that  there  is  a  large  band  hanging  loose  in  the  lumen,  /"is  thick-walled 
and  Fig.  50  is  an  enlarged  view  of  another  section  of  the  same  vein,  g  is  a  thick-walled  vein 
with  bands  hanging  across  its  lumen.  "Fig.  49  is  an  enlarged  view  of  the  vein  g. 


FIG.  47. 


DISEASE  OF  THE  RADIAL  ARTERIES  AND  VEINS          65 

during  the  life  of  the  patient,  when  the  pulse  was  felt  at  the  wrist, 
that  the  vessel  or  vessels  were  stiff.  Such  stiffening  as  this,  which  is 
ascertained  to  be  present  by  feeling  the  pulse,  is  commonly  consid- 
ered to  denote  that  the  radial  artery  is  thickened  owing  to  atheroma 
or  to  calcification  of  its  walls  or  to  some  other  disease.  My  own 
experience  has  proved  to  me  that  under  such  circumstances  the  veins 
often  participate  in  the  disease,  and  a  glance  at  the  drawings  at  once 
shows  that  all  of  the  veins  as  well  as  the  artery  are  diseased.  Thick- 
ening of  the  walls  of  the  blood-vessels,  which  it  is  well  known  occurs 
almost  inevitably  in  old  people,  is  very  curious,  but  there  is  almost 
nothing  known  of  its  cause  except  that  fibrosis  is  a  part  of  the  pro- 
cess. This,  however,  does  not  touch  the  real  question  of  the  cause. 
That  similar  thickening  of  the  blood-vessel  walls  should  occur  also 
in  young  people  (the  vessels  seen  in  Fig.  47  were  taken  from  the  body 
of  a  boy  of  fifteen  years)  is  even  stranger  and  still  more  beyond 
our  power  to  explain.  In  my  book  on  the  "Origin  of  Disease" 
I  have  discussed  the  question  of  this  strange  condition,  which  is  like 
age  in  youth,  and  in  that  book,  as  well  as  in  this  one,  there  are  in- 
cluded a  number  of  drawings  of  blood-vessels  from  the  bodies  of 
young  persons  which  show  the  thickening  of  their  walls  that  is  gen- 
erally believed  to  be  characteristic  of  age.  The  boy  from  whom  the 
blood-vessels  (Fig.  47)  were  obtained  died  of  acute  meningitis  and  he 
was  ill  for  many  weeks.  During  the  course  of  the  illness  he  became 
emaciated  to  the  last  degree  and,  as  commonly  occurs  under  the 
circumstances,  he  assumed  more  and  more  the  appearance  and  ex- 
pression of  age.  The  tissues  were  dry  and  shrivelled,  and  the  face 
especially  resembled  that  of  an  old  man,  the  skin  being  wrinkled  and 
tightly  drawn  over  the  bones,  which  stood  out,  and  the  head  looked 
almost  like  a  dried  skull.  It  is  pitiable  to  see  a  boy,  and  perhaps 
even  more  so  to  see  an  infant  dying  of  wasting  disease,  assume  the 
expression  of  old  age.  Examination  of  the  body  under  such  circum- 
stances invariably  reveals  the  existence  of  some  of  the  lesions  of  age, 
and  among  them  of  thickening  of  the  blood-vessels. 

It  is  easy  to  see  that  the  artery  pictured  in  Fig.  47  is  diseased,  for 
its  wall  is  thick,  and  Fig.  48,  which  is  an  illustration  of  a  portion  of 
it  more  highly  magnified,  shows  other  abnormal  conditions.  The 
intima  probably  is  a  little  thicker  than  is  normal,  and  the  plicated 
membrane  exhibits  a  curious  condition  which  quite  commonly 
5 


66  HUMAN  BLOOD-VESSELS 

exists  in  arteries  under  such  circumstances  and  which  must  be  owing 
to  disease.  In  some  places  it  is  distinctly  visible,  and  in  others  it 
cannot  be  seen.  Its  disappearance  must  be  due  to  its  having  become 
cellular  and  blended  with  the  intima  and  muscularis.  The  normal 
plicated  membrane  is  acellular  and  clear  like  the  cornea  of  the  eye, 
but  under  the  influence  of  disease,  especially  of  inflammation,  it  be- 
comes cellular  and  opaque.  To  the  left  in  Fig.  48  the  plicated  mem- 
brane is  easily  distinguishable,  but  to  the  right  it  cannot  be  seen. 
This  form  of  disease  I  have  described  in  my  book  on  the  "  Origin  of 
Disease  "  (page  43,  Fig.  8),  and  I  have  shown  that  it  may  occur  even 

in  infancy. 

Fig.  48,  which  depicts  a  portion  of  the  artery  more  highly  mag- 
nified, shows  better  than  Fig.  47  that  the  muscularis  is  diseased.  It 
is  thicker  and  less  rich  in  nuclei  than  is  natural  in  involuntary  muscu- 
lar tissue.  This  I  believe  to  be  due  to  the  growth  of  morbid  fibroid 
tissue  in  the  muscularis.  The  effect  of  the  post-mortem  shrinkage  is 
strikingly  shown  by  the  situation  of  the  muscular  nuclei,  which  are 
irregularly  placed,  instead  of  having  their  greatest  length  running  in 
the  direction  of  the  circumference  of  the  vessel,  as  is  seen  in  Fig.  1 1, 
which  exhibits  more  nearly  the  conditions  existing  during  life.  Fig. 
47  shows  that  all  the  veins  included  are  diseased.  The  walls  of  all 
of  them  are  thicker  than  normal,  and  two  of  them,  c  and^-,  have  shreds 
or  partitions  which  are  partly,  at  least,  formed  of  the  intima  hanging  in 
their  openings. 

In  Fig.  49  is  seen  the  vein  g  of  Fig.  47  more  highly  magnified. 
The  disease  is  a  combination  of  the  morbid  conditions  shown  by 
Figs.  34  and  35.  There  are  two  strings  hanging  across  the  calibre 
of  the  vein.  Parts  of  these  are  light  and  are  composed  of  material 
like  the  structureless  endothelium  of  the  intima,  and  there  are  endo- 
thelial  nuclei  in  them.  Near  the  points  of  attachment  of  the  strings 
they  are  heavier  and  contain  muscular  tissue.  The  wall  of  the  vein 
is  thicker  than  is  natural,  and  much  the  greatest  part  of  it  is  com- 
posed of  loose-meshed  diseased  involuntary  muscle.  The  muscular 
tissue,  instead  of  being  composed  almost  entirely  of  threads  and  elon- 
gated nuclei  running  principally  in  the  direction  of  the  circumference  of 
the  vessel  wall,  as  is  natural,  is  formed  of  material  which  does  not  ap- 
pear to  have  any  orderly  arrangement.  There  are  scattered  bits  of 
muscle  which  run  in  various  directions,  and  between  these  are  por- 


FIG.  49. — DISEASED  RADIAL  VEIN.     (X  50.) 

The  vein  g  from  Fig.  47  more  highly  magnified.  There  are  two  strings  or  partitions  ex- 
tending across  the  lumen  of  the  vein.  These  look  like  thickened  shreds  of  endothelium  from 
the  lining  of  the  vein.  There  are  also  several  irregular  masses  of  tissue  projecting  into  the 
lumen.  The  wall  of  the  vein  is  of  very  varying  thickness,  and  it  is  composed  of  muscular 
tissue  and  morbid  fibroid  tissue  which  has  grown  in  it.  The  whole  appearance  is  like 
another  phase  of  the  state  of  disease  shown  by  Figs.  34  and  35. 


FIG.  49. 


FIG.  49.— DISEASED  RADIAL  VEIN.     (X  50.) 

The  vein^  from  Fig.  47  more  highly  magnified.  There  are  two  strings  or  partitions  e> 
tending  across  the  lumen  of  the  vein.  These  look  like  thickened  shreds  of  endothelium  fro 
the  lining  of  the  vein.  There  are  also  several  irregular  masses  of  tissue  projecting 


DISEASE  OF  THE  RADIAL  ARTERIES  AND  VEINS          67 

tions  of  fibrous  tissue.  This  vessel,  as  much  as  any  one  that  I  have 
ever  examined,  seems  to  me  to  demonstrate  that  part  of  the  cause  of 
such  disease  is  the  irregular  growth  of  fibrous  tissue  in  places  where 
under  natural  conditions  there  is  very  little  of  it.  The  contrast  be- 
tween such  involuntary  muscle  as  this  and  the  muscularis  of  a  normal 
vein  is  most  striking.  Altogether  this  vein  is  a  curious  one  and  the 
disease  is  very  interesting. 

Fig.  50  is  an  enlarged  view  of  the  vein  f,  Fig.  47.  The  charac- 
ter of  the  disease  is  very  similar  to  that  shown  by  Fig.  34.  The 
calibre  of  the  vein  is  small  and  it  contains  blood-corpuscles.  The 
wall,  which  is  greatly  thickened,  is  composed  principally  of  diseased 
muscular  tissue,  and  the  drawing  shows  that  the  fibres  and  the  nuclei 
of  the  muscle  have  been  torn  apart  by  fibrous  tissue  which  has  insin- 
uated itself  between  them.  In  this  vein,  as  well  as  in  Figs.  34  and 
31,  the  morbid  fibrous  tissue  can  with  certainty  be  recognized  as  such. 
In  some  of  the  drawings  it  is  possible  to  see  that  the  muscular  tissue 
is  torn  apart,  but  the  nature  of  the  material  lying  between  its  fibres 
cannot  be  definitely  identified.  This  may  be  because  of  imperfect 
preservation  of  the  tissue,  or  owing  to  poor  staining,  or  there  may  be 
some  other  reason  why  the  spaces  between  the  shreds  of  muscle  look 
as  if  they  were  empty.  The  intima  shown  in  Fig.  50  is  thicker  than 
that  of  any  of  the  other  veins  of  which  drawings  are  included.  There 
is  no  law  that  I  have  been  able  to  discover  governing  the  relative 
amount  of  thickening  of  the  intima  and  muscularis  of  arteries  and  veins 
that  takes  place  as  a  result  of  disease.  Most  of  the  thickened  veins 
that  I  have  studied  have  exhibited  disease  and  increase  of  the  mus- 
cularis, but  the  condition  of  the  intima  has  varied.  In  none  of  them 
has  the  intima  been  thickened  to  anything  like  the  degree  that  it  is 
common  to  see  in  arteries.  Fig.  50  shows  greater  thickening  of  the 
intima  than  any  other  vein  that  I  can  remember  to  have  seen.  On 
the  other  hand,  it  is  quite  certain  that  in  arteries  with  thick  walls,  it  is 
the  intima  that  is  diseased  and  thickened  in  the  great  majority  of 
cases.  The  radial  is  more  liable  to  undergo  thickening  of  the  mus- 
cularis than  any  other  artery  that  I  have  examined,  but,  in  addi- 
tion, as  has  been  shown  in  this  chapter,  there  is  apt  to  be  more  or 
less  disease  of  the  intima  as  well.  The  kind  of  thickening  and  disease 
of  the  intima  that  is  common  in  the  arteries  of  the  heart  and  kidney, 
the  nature  of  which  will  be  shown  in  the  chapters  upon  those  two 


68  HUMAN  BLOOD-VESSELS 

organs,  I  have  never  seen  in  a  vein,  and  it  certainly  cannot  be  as 
common  in  the  veins  as  it  is  in  the  arteries.  There  must  be  some 
reason  why  arteries  are  so  much  more  liable  to  disease  of  their  lining 
membrane  than  veins,  but,  as  has  been  said,  almost  nothing,  is  yet 
known  of  the  law  which  governs  the  relative  degrees  of  thickening  of 
the  two  tunics  that  occur.  Even  less  is  known  of  disease  of  the  adven- 
titia  ;  but  I  have  already  discussed  this  subject  in  connection  with  the 
peculiarities  of  the  blood-vessels  shown  by  Fig.  33.  The  confusion 
which  arises  owing  to  the  difficulty  in  distinguishing  between  adventitia 
and  perivascular  connective  tissue  is  a  subject  that  I  have  more  than 
once  mentioned,  and  it  is  one  that  has  always  to  be  contended  with  in 
studying  the  adventitia  both  of  arteries  and  veins. 

My  discussion  of  the  subject  of  disease  of  the  radial  arteries  and 
veins  is  quite  incomplete,  but  I  think  I  have  been  able  to  add  a  little 
to  what  is  known  of  it.  The  observation  that  the  veins  as  well  as  the 
radial  artery  are  thickened,  when  thickening  is  discovered  by  feeling 
the  pulse  at  the  wrist,  is  one  of  importance,  and  the  nature  of  the 
lesions  of  the  radial  veins  is  very  curious.  The  most  striking  of  these 
is  the  proliferation  of  the  intima,  which  produces  in  the  calibre  of  the 
vein  a  mass  that  in  section  looks  like  a  bunch  of  entangled  earth- 
worms. Veins  so  diseased  are  most  curious  objects  to  examine,  but 
the  cause  of  the  disease  is  as  yet  unexplainable.  More  extended 
study  of  this  disease  of  the  veins  which  causes  thickening  of  their 
walls  and  reduction  of  their  openings,  and  therefore  interference  with 
their  power  to  carry  blood,  may  some  day  lead  toward  an  explanation 
of  that  strange  and  widely  prevalent  disease — fibroid  degeneration. 
There  is  no  part  of  the  body  that  is  not  liable  to  be  affected  by 
it,  nor  is  there  any  period  of  life  at  which  human  beings  are  secure 
from  its  insidious  invasion.  It  is  an  inevitable  accompaniment  of  age, 
and  it  often  attacks  young  infants.  There  is  good  reason  to  believe 
that  it  has  its  beginnings  in  or  near  the  blood-vessels,  but  just  where 
and  how  it  begins  has  not  yet  been  discovered.  The  normal  and 
diseased  veins  which  are  shown  by  the  drawings  indicate  that  in 
structure  they  differ  from  arteries  more  decidedly  than  is  generally 
supposed,  and  that  the  ordinary  descriptions  of  veins  need  a  good 
deal  of  revision. 


FIG.  50. — DISEASED  RADIAL  VEIN.     (X  50.) 

Another  section  of  the  vein  f  from  Fig.  47  more  highly  magnified.  The  wall  is  very 
thick,  and  it  is  composed  in  great  part  of  muscular  tissue  into  which  a  large  amount  of  mor- 
bid fibroid  tissue  has  grown.  The  intima  also  is  thickened.  The  disease  is  similar  to  that 
shown  by  Fig.  34. 


FIG.  50. 


CHAPTER     VII 

THE  BLOOD-VESSELS  IN  INFLAMMATION,   IN  TUBERCULOSIS, 
AND  IN  SYPHILIS 

As  a  result  of  inflammation,  of  tuberculosis,  and  of  syphilis  the 
tissues  undergo  changes  and  the  blood-vessels  are  often  diseased. 
These  lesions  of  the  vascular  system  have  been  quite  extensively 
studied,  and  it  has  been  supposed  that  the  different  diseases  could 
be  recognized  from  a  study  of  the  pathological  changes  of  the  blood- 
vessels that  they  cause.  My  own  investigations  have  made  me  be- 
lieve this  to  be  impossible.  The  mistake  is  made  of  studying  the 
tissues  of  a  man  who  has  died  of  one  of  the  diseases,  and  then,  if 
lesions  of  the  blood-vessels  are  found,  of  supposing  that  they  are 
peculiar  to  the  disease  of  which  the  patient  died.  No  consideration 
is  given  to  the  facts  that  the  vascular  changes  may  be  incidental  and 
that  similar  lesions  may  arise  from  other  causes.  It  is  my  opinion 
that  there  is  no  lesion  of  the  blood-vessels  which  is  peculiar  to  in- 
flammation, to  tuberculosis,  or  to  syphilis,  and  this  opinion  is  based 
upon  the  examination  of  a  great  many  blood-vessels.  The  mistake 
of  supposing  that  particular  diseases  can  be  recognized  from  the 
peculiarities  of  a  few  cells,  or  by  the  appearance  of  some  minute 
lesion  of  a  blood-vessel  which  can  be  seen  only  with  the  microscope, 
is  much  less  common  to-day  than  it  was  a  few  years  ago.  It  is  ac- 
knowledged, for  instance,  that  tubercular  disease  cannot  be  recognized 
by  the  examination  of  any  one  field  under  the  microscope,  because 
much  of  the  tubercular  tissue  is  like  other  tissues,  and  even  giant 
cells,  which  at  one  time  were  believed  to  be  peculiar  to  the  tubercular 
process,  are  now  well  known  to  be  due  to  other  causes  and  to  be 
often  found  in  non-tubercular  tissues.  Tuberculosis  can  only  be 
recognized  post  mortem  by  the  study  of  the  disease  in  the  gross 
together  with  a  careful  consideration  of  all  the  information  to  be 
derived  from  the  fullest  examination  of  all  the  tissues  and  in  every 
known  way.  There  is  no  cell,  nor  is  there  any  grouping  of  cells,  that 
is  peculiar  to  tuberculosis.  The  same  thing  is  true  of  inflammation 
and  of  syphilis.  In  studying  the  tissues  of  persons  who  have  died 

69 


70  HUMAN  BLOOD-VESSELS 

while  suffering  with  the  diseases  under  consideration,  the  points  that 
have  struck  me  most  forcibly  are  the  similarity  of  the  lesions  of  the 
blood-vessels  found  in  all  three,  and,  on  the  other  hand,  the  frequent 
entire  absence  of  disease  of  the  blood-vessels  in  cases  of  those  diseases 
which  are  generally  supposed  most  surely  to  produce  it.  My  illustra- 
tions show  the  general  similarity  of  the  lesions. 

Fig.  51  is  an  illustration  of  a  portion  of  the  wall  of  the  inflamed 
and  atheromatous  aorta  of  a  negro  man  fifty  years  old  who  died  of 
endocarditis.  The  adventitia  and  a  portion  of  the  muscularis  are 
included  by  the  drawing.  There  are  several  areas  which  distinctly 
show  inflammatory  cellular  exudation,  but  the  most  peculiar  feature 
here  observed  is  the  condition  of  the  blood-vessels.  The  largest 
one  of  these  vasa  vasorum,  of  which  three  large  ones  are  included, 
is  very  thick -walled  and  is  of  unnatural  appearance.  There  are  other 
smaller  vessels  shown,  but  they  are  thin-walled  and  are  like  capil- 
laries in  structure.  It  is  impossible  to  ascertain  whether  the  three 
thick-walled  vessels  are  new  growths  which  resulted  from  the  effects 
of  the  inflammation  or  are  only  natural  blood-vessels  changed  and 
thickened  by  disease  which  existed  when  the  patient  was  in  apparent 
health.  My  own  inclination  is  to  believe  that  they  are  new  vessels 
which  failed  to  attain  a  natural  development.  The  middle  one  of  the 
three  is  almost  a  solid  cord,  for  there  is  only  a  very  minute  channel 
in  it  and  that  is  not  centrally  placed.  The  tissue  of  which  it  is  com- 
posed is  unlike  any  that  exists  in  natural  blood-vessels.  The  two 
others  also  are  totally  unlike  normal  vessels.  The  manner  in  which  a 
bit  of  the  adventitia  is  dragged  into  an  arch  over  one  of  these  vessels 
produces  an  odd  effect  The  distortion  must  be  the  result  of  increase 
in  size  of  the  vessel  which  was  at  one  time  smaller.  As  it  grew  it 
pushed  the  adjacent  tissue  to  one  side  and  caused  the  formation  of 
the  arch.  The  subject  of  the  growth  of  new  blood-vessels  is  discussed 
in  Chapter  III.  It  is  curious  to  find  such  vessels  in  the  wall  of  the 
inflamed  and  thickened  aorta  of  a  man  who  died  of  endocarditis. 

Fig.  52  represents  an  arteriole  and  a  venule  of  the  ileum  of  a 
woman  twenty-six  years  old  who  died  of  typhoid  fever.  The  vessels 
are  in  the  muscular  layer  of  an  ulcerated  portion  of  the  ileum,  the 
surrounding  tissue  being  in  a  state  of  acute  inflammation  and  the 
mucous  layer  having  sloughed  away.  The  vessels  lie  in  an  area 
of  inflamed  tissue  and  are  surrounded  by  common  round  exudation 


FIG.  51. — DISEASED  AND  NEW  BLOOD-VESSELS  IN  THE  WALL  OF  THE  AORTA.     (X  50.) 

From  a  negro  man  fifty  years  old  who  died  of  endocarditis.  The  drawing  includes  the 
entire  thickness  of  the  adventitia  and  part  of  the  muscularis.  The  vasa  vasorum  lie  in  the 
adventitia.  Directly  above  the  muscular  tissue  is  a  thick-walled  vessel  over  which  passes  an 
arched  string  of  fibrous  tissue.  Above  this  is  another  vessel  which  has  been  converted 
into  an  almost  solid  cord,  for  there  is  no  opening  in  it  but  a  small  one  at  the  side.  Above 
and  to  the  right  of  this  is  another  thick-walled  vessel  with  a  small,  laterally  placed  opening 
which  contains  some  blood-corpuscles.  It  is  impossible  to  be  certain  whether  such  vessels  as 
these  three  are  diseased  vasa  vasorum  or  if  they  are  new  vessels.  There  is  at  least  one 
thin-walled  vessel  like  a  capillary  which  contains  blood-corpuscles.  It  lies  above  and  to  the 
left  of  the  middle  one  of  the  thick-walled  blood-vessels. 


FIG.  52. — DISEASED  ARTERIOLE  AND  VENULE  OF  THE  ILEUM.     (X  240.) 

From  a  woman  twenty-six  years  old  who  died  of  typhoid  fever.  The  vessels  are  in  the 
muscular  layer  of  an  ulcerated  portion  of  the  ileum,  the  surrounding  tissue  is  in  a  state  of 
acute  inflammation,  and  the  mucous  layer  has  sloughed  away,  a  is  the  arteriole  and  v  the 
venule.  Neither  of  them  has  the  appearance  of  ordinary  blood-vessels, — the  round  cells  of 
inflammation  have  invaded  the  walls  of  both.  The  calibre  of  the  arteriole  is  nearly  closed 
and  its  wall  is  very  thick.  The  wall  of  the  vein,  on  the  other  hand,  is  thin  and  composed 
of  fibrous  tissue  and  round  cells. 


FIG.  51. 


FIG.   52. 


INFLAMMATION;    TUBERCULOSIS;    SYPHILIS  71 

cells.  Exactly  similar  ones  are  to  be  seen  in  the  walls  of  the  two 
blood-vessels,  and  the  cells  even  project  into  the  openings.  The  wall 
of  the  arteriole  is  very  thick  and  its  lumen  is  almost  closed.  The 
venule  is  structurally  much  more  like  a  capillary  than  like  an  ordi- 
nary vein.  Its  wall  is  not  composed  of  three  layers — intima,  muscu- 
laris,  and  adventitia — but  of  fibrous  material  containing  cells.  This 
fibrous  tissue  is  like  endothelium,  but  it  is  not  disposed  in  a  single 
layer  as  the  endothelium  of  the  capillaries  of  the  smallest  size  is.  The 
cells  do  not  look  as  if  they  were  swollen  and  rounded  endothelial 
cells,  but  the  appearance  suggests  that  the  inflammatory  process  had 
invaded  the  venule  as  well  as  the  surrounding  tissue,  and  that  some 
of  the  cells  in  its  wall  are  due  to  this  invasion  and  are  therefore  of 
foreign  origin.  The  processes  of  inflammation  as  they  have  been 
studied  in  living  animals — in  the  cornea  of  the  eye,  for  instance,  and 
in  the  web  of  the  frog's  foot — are  well  known  to  pathologists.  The 
changes  of  the  rate  of  motion  of  the  blood  current,  the  clogging  of 
the  corpuscles  in  the  vessels,  and  their  passage  through  the  walls  of 
the  capillaries  which  produces  infiltration  of  the  adjacent  tissues,  have 
all  been  seen  and  their  various  stages  have  been  studied.  Such  stud- 
ies have  given  an  understanding  of  acute  inflammation  which  is  to  a 
certain  extent  complete,  but  it  has  not  as  yet  been  possible  to  study 
chronic  inflammation  with  anything  like  the  same  completeness,  nor 
has  any  one  in  the  same  way  seen  the  actual  workings  of  inflammation 
upon  human  tissues. 

Some  of  the  effects  of  chronic  inflammation  upon  human  tissues  are 
hard  to  explain  by  what  has  been  learned  from  the  study  of  experi- 
mental inflammation  of  the  tissues  of  the  lower  animals,  for  such  studies 
are  necessarily  confined,  as  has  been  said,  to  acute  inflammation  alone. 
The  rest  of  my  drawings  which  illustrate  the  condition  of  the  blood- 
vessels in  inflammation,  in  tuberculosis,  and  in  syphilis  are  from  the 
brain  and  spinal  cord  and  their  meninges.  When  tissues  like  the  me- 
ninges  of  the  brain  and  spinal  cord  are  attacked  by  inflammation  or 
by  the  tubercular  process,  the  veins  appear  to  be  attacked  earlier  and 
to  suffer  more  than  the  arteries.  In  sections  of  inflamed  and  tuber- 
cular meninges,  the  round  cells  can  be  seen  in  the  walls  of  the  veins 
when  arteries  lying  near  are  almost  normal.  The  arteries  do  become 
affected,  but  it  seems  as  if  they  were  attacked  later  than  the  veins. 
It  is  not  at  present  known  whether  this  is  because  veins  are  composed 


72  HUMAN  BLOOD-VESSELS 

of  tissue  of  a  loose  texture  and  therefore  they  fall  an  easy  prey  to  a 
process  like  cellular  infiltration,  while  arteries — which  are  naturally  of  a 
firm  and  dense  structure — resist  the  entrance  of  the  cells  into  their 
walls,  or  if  there  is  some  other  reason  dependent  upon  the  nature  or 
function  of  the  veins.  The  fact,  however,  is  beyond  question,  and  one 
of  the  most  striking  features  of  sections  of  inflamed  and  tubercular 
meninges  is  that  the  walls  of  the  veins  are  infiltrated  and  their  calibres 
obliterated  by  the  cells,  while  the  arteries  remain  much  less  diseased. 

Fig.  53  is  a  picture  of  an  artery  and  veins  from  the  meninges  of  the 
spinal  cord  of  a  boy  six  years  old  who  died  of  acute  meningitis.  The 
meningeal  tissue  around  the  vessels  is  inflamed.  The  artery  is  of 
nearly  natural  appearance  upon  one  side,  while  on  the  other  the  round 
cells  of  inflammation  have  invaded  it  and  lie  close  to  it  both  upon  its 
outer  side  and  within  its  calibre.  The  veins  are  much  more  diseased 
than  the  artery.  The  most  diseased  vein,  which  is  the  one  to  the  left, 
is  almost  closed  by  the  cells,  and  the  structure  of  its  wall  cannot  be 
clearly  distinguished,  owing  to  the  inflammatory  infiltration  which 
covers  up  and  hides  the  natural  tissue.  The  vein  to  the  right  is  much 
less  diseased.  In  conditions  of  inflammation  like  this,  the  veins  are 
generally  attacked  earlier  than  the  arteries  and  are  more  extensively 
diseased.  This  may  be  because  of  their  structure,  which  is  looser  and 
more  open,  rendering  their  walls  more  easy  of  penetration  by  the  in- 
vading cells.  The  process  of  disease  represented  by  Fig.  53,  which 
is  purely  inflammatory,  cannot  possibly  be  distinguished  by  its 
appearance  from  tubercular  disease  of  blood-vessels. 

Fig.  54  shows  a  group  of  blood-vessels  of  the  meninges  of  the  spinal 
cord  of  a  negro  woman  twenty-five  years  old  who  died  of  tubercular 
meningitis,  pulmonary  tuberculosis,  and  gastric  ulcer.  The  meningitis 
is  said  to  be  tubercular,  because  the  woman  had  pulmonary  tubercu- 
losis, and  not  because  of  any  peculiar  appearance  of  the  blood-vessels 
or  of  their  surrounding  tissue.  The  effect  of  the  disease  upon  both 
the  blood-vessels  and  the  meningeal  tissue  is  exactly  similar  to  that 
produced  by  inflammation  (see,  for  example,  Fig.  53).  The  meningeal 
tissue  is  infiltrated  with  round  cells,  and  the  same  process  of  disease  has 
attacked  the  blood-vessels,  which  also  are  surrounded  by  the  cells. 
The  walls  of  the  blood-vessels  are  more  or  less  infiltrated.  Of  the  four 
largest  vessels  that  are  included  in  the  drawing,  one  is  easily  recognized 
as  an  artery  and  a  second  as  a  vein,  but  the  two  others  are  so  altered 


FIG.  53. — ARTERY  AND  VEINS  IN  INFLAMED   PIA-ARACHNOID  OF  THE  CORD.     (X  50.) 

From  a  boy  six  years  old  who  died  of  acute  meningitis,  a,  an  artery,  and  v,  v,  veins. 
The  tissue  is  infiltrated  with  inflammation  cells,  and  the  cells  have  forced  themselves  into  the 
blood-vessels.  The  appearance  suggests  that  the  inflammation  began  in  the  fibrous  tissue  and 
then  forced  itself  into  the  blood-vessels  as  it  extended.  The  artery  is  hardly  diseased  upon 
the  one  side,  and  on  the  other  the  inflammation  cells  have  passed  entirely  through  its  wall 
and  some  of  them  lie  within  its  lumen.  The  veins  are  much  more  diseased  than  the  artery. 
The  one  to  the  left  is  almost  closed  and  its  structure  cannot  be  distinguished.  In  the  vein  to 
the  right  the  disease  is  less  extensive.  This  process  of  acute  inflammation  cannot  be  distin- 
guished by  its  appearance  from  tubercular  disease  of  blood-vessels. 

FIG.  54. — BLOOD-VESSELS  OF  TUBERCULAR  MENINGITIS  OF  THE  CORD.     (X  50.) 

From  a  negro  woman  twenty-five  years  old  who  died  of  tubercular  meningitis  and  pujmo- 
nary  tuberculosis  and  gastric  ulcer,  a,  b,  c,  and  d  are  placed  directly  over  four  blood-vessels 
which  lie  in  the  diseased  pia-arachnoid.  a,  an  arteriole,  and  l>,  a  venule ;  c  and  d  are  so 
much  diseased  that  it  is  impossible  to  distinguish  what  kind  of  vessels  they  are.  All  four  are 
infiltrated,  and  in  all  of  them  it  looks  as  if  the  disease  had  originated  outside  and  then  in- 
vaded the  blood-vessels  rather  than  had  its  origin  in  the  vessels  themselves.  The  appear- 
ances of  the  tubercular  disease  of  these  blood-vessels  are  exactly  the  same  as  those  produced 
by  simple  inflammatory  meningitis.  (See  Fig.  53.) 


FIG.  53. 


INFLAMMATION;    TUBERCULOSIS;    SYPHILIS  73 

by  disease  that  it  is  impossible  to  ascertain  whether  they  are  arteries  or 
veins.  This  alteration  of  the  natural  characteristics  of  blood-vessels  by 
disease,  so  that  they  cannot  be  recognized,  is  a  common  occurrence. 

Figs.  55  and  56  depict  an  artery  and  a  vein  from  a  section  of  the 
spinal  cord  and  meninges  of  the  same  patient  as  Fig.  54.  As  is  the 
case  in  Fig.  54,  the  disease  shown  by  Figs.  55  and  56  could  not  be 
recognized  as  tubercular  had  it  not  been  that  the  patient  had  pulmo- 
nary tuberculosis.  There  is  simply  a  cell  infiltration  similar  in  every 
respect  to  that  which  takes  place  in  inflammation.  The  artery  (Fig. 
55)  is  surrounded  with  round  infiltration  cells,  and  the  adventitia  has 
been  invaded  by  them  so  that  it  cannot  be  distinguished  as  fibrous 
tissue.  The  muscular  coat  shows  no  disease  and  is  easily  recognized. 
There  are  slight  thickening  and  proliferation  of  the  intima,  and  blood- 
corpuscles  fill  the  greater  part  of  the  lumen.  The  vein  (Fig.  56)  is  sur- 
rounded by  round  cells,  and  these  have  infiltrated  it  so  that  the  tissue 
of  the  wall  can  be  distinguished  at  only  a  small  portion  of  the  circum- 
ference. The  disease  has  progressed  much  further  in  this  vein  than  in 
the  artery  (Fig.  55)  and  the  drawing  gives  a  graphic  and  very  correct 
impression  of  the  effect  which  is  produced  by  inflammation  and  tuber- 
culosis upon  veins.  The  cell  infiltration  has  progressed  so  far  that  the 
vessel  wall  appears  as  if  composed  almost  entirely  of  the  exudate  cells. 
There  is  hardly  any  distinguishable  remnant  of  the  natural  tissue  of 
the  vein  left. 

Fig-  57  is  taken  from  the  same  case  as  the  three  drawings  last 
described.  It  is  probably  a  vein,  but  of  this  it  is  impossible  to  be 
certain.  The  disease  has  progressed  even  further  than  in  the  ves- 
sels previously  described.  The  surrounding  tissue  and  the  wall  are 
overwhelmed  by  the  cellular  infiltration,  and  the  lumen  is  nearly 
closed  by  the  cells  and  clot.  Clot,  infiltration  cells,  vessel-wall,  and 
the  surrounding  meningeal  tissue  are  all  blended  into  a  single  whole, 
of  which  the  component  parts  cannot  be  distinctly  recognized.  The 
disease  of  this  vessel  could  not  have  been  known  to  be  tuber- 
cular from  its  appearance  alone,  for  the  effect  produced  is  exactly 
the  same  as  that  which  so  commonly  results  from  inflammation.  As 
has  already  been  said  of  the  three  previously  described  drawings,  the 
disease  is  only  called  tubercular  meningitis  because  the  patient  had 
pulmonary  tuberculosis.  If  such  a  thing  be  possible  as  a  simple  in- 
flammatory meningitis  in  a  person  with  pulmonary  tuberculosis,  this 


74  HUMAN  BLOOD-VESSELS 

case  may  well  have  been  one  of  that  kind.  The  lesions  of  the  spinal 
cord  and  meninges  are  exactly  similar  to  those  found  in  cases  of 
simple  inflammatory  meningitis.  There  was  not  a  single  miliary 
tubercle  found  anywhere,  for  the  lesions  of  the  lungs  were  not  of  that 
character,  nor  were  there  any  miliary  tubercles  of  the  spinal  meninges 
discovered. 

Fig.  58  illustrates  arteries  and  veins  from  the  lumbar  portion  of 
the  spinal  cord  of  a  negro  man  twenty-three  years  old  who  died  of 
brain  syphilis.  There  are  one  good-sized  artery  and  two  small  arteri- 
oles,  and  two  veins,  one  of  which  is  much  larger  than  the  other. 
The  arteries  and  veins  are  easily  distinguished  from  each  other  by 
their  appearances.  Syphilis  is  supposed  almost  necessarily  to  pro- 
duce alterations  of  the  blood-vessels,  and  yet  this  group  of  vessels  of 
the  cord  of  a  man  who  died  of  brain  syphilis  do  not  exhibit  any 
greater  departure  from  the  standard  of  the  normal  than  it  is  common 
to  find  in  human  beings  even  so  young  as  twenty-three  years  of  age. 
No  disease  of  the  blood-vessels  of  other  parts  of  the  cord  nor  of  the 
brain  of  this  man  was  found.  The  arteries  (Fig.  58)  might  be  said  to 
be  a  little  thicker  walled  than  they  should  be,  and  in  the  larger  one 
of  them  the  intima  is  thicker  upon  one  side  than  upon  the  other ; 
but  this  imperfection,  for  imperfection  it  undoubtedly  must  be,  is  so 
common  that  it  is  difficult  to  find  arteries  of  an  adult  without  more  or 
less  of  it.  The  veins  are  not  distinctively  diseased  in  anyway.  Their 
walls  are  not  composed  of  three  coats,  as  it  is  commonly  taught  that 
veins  of  this  size  are.  They  are  formed  of  a  loose-meshed  fibrous 
tissue  which  is  in  many  layers,  and  they  are  structurally  much  more 
like  large  and  thick-walled  capillaries  than  like  ordinary  typical  veins. 
Such  vessels,  whether  they  be  called  veins  or  return  capillaries,  are 
very  common.  The  striking  feature  which  these  vessels  are  intended 
to  illustrate  is,  that  in  a  case  of  syphilis  the  blood-vessels  are  nearly 
normal,  although  syphilis  is  the  disease  to  which  more  than  to  any 
other  endarteritis  is  supposed  to  be  peculiar.  I  have  not  examined 
the  blood-vessels  in  a  very  large  number  of  cases  of  syphilis,  but  in 
those  that  I  have  examined,  and  there  have  been  several  of  them,  I 
have  been  surprised  to  find  vascular  disease  absent. 

The  question  to  what  degree  the  effects  produced  by  the  inflam- 
matory process  upon  large  arteries  and  veins  resemble  those  produced 
upon  capillaries,  is  an  interesting  one  and  is  very  important.  The 


FIG.  55. — TUBERCUI.AR  INFLAMMATION  OF  AN  ARTERY  OF  THE  CORD.     (X  50.) 

From  the  same  case  as  Fig.  54.  There  is  infiltration  of  the  tissue  around  the  artery  just 
as  there  is  around  the  vein  (Fig.  56),  which  is  from  the  same  section.  The  disease  is  much 
less  extensive  in  the  artery  than  in  the  vein. 

FIG.  56. — TUBERCULAR  INFLAMMATION  OF  A  VEIN  OF  THE  CORD.     (X  50.) 

From  the  same  case  as  Fig.  55.  Very  little  of  the  wall  of  the  vein  can  be  distinguished, 
for  the  cell  infiltration  is  so  great  as  to  change  it  beyond  recognition.  The  cells  appear  to  be 
invading  the  wall  of  the  vein  from  the  outside,  and  the  appearance  suggests  that  the  disease 
did  not  originate  within  the  vessel  but  in  the  surrounding  tissue. 


FIG.  56. 


INFLAMMATION;    TUBERCULOSIS;    SYPHILIS  75 

wandering  of  the  corpuscles  through  the  capillary  walls,  which  has  so 
often  been  watched  in  inflammation  experimentally  induced  in  the 
tissues  of  the  lower  animals,  is  well  known,  but  it  is  impossible  to  be- 
lieve that  anything  like  it  occurs  in  the  case  of  the  large  arteries  and 
veins  which  have  thick  walls  of  definite  structure.  It  is  unlikely  that 
the  blood-corpuscles  pass  through  the  walls  of  arteries  and  veins  at 
all,  unless  possibly  of  those  of  the  most  minute  size.  A  study  of  the 
appearances  of  the  inflamed  arteries  and  veins,  of  which  drawings  are 
included  in  this  chapter,  and  of  the  blood-vessels  of  tubercular  per- 
sons which  are  exactly  similarly  affected,  drives  one  to  the  conclusion 
that  these  diseases  attack  the  blood-vessels  from  without  The  com- 
monest known  diseases  of  the  arteries — and  they  occur  in  veins  too, 
although  much  less  frequently — are  thickening  and  ulceration  of  the 
intima.  These  bear  no  resemblance  to  the  lesions  of  inflammation 
and  of  tuberculosis  shown  by  the  drawings,  but  present  a  striking 
contrast  to  them.  In  the  one  case  there  is  ulceration  or  thickening 
of  the  lining  of  the  vessel,  which  produces  a  well-organized  tissue  of 
quite  different  appearance  from  normal  intima.  The  whole  process 
evidently  has  its  origin  within  the  vessel,  and  it  often  produces  little 
or  no  change  of  the  muscularis  and  adventitia,  while  in  the  other  case 
the  arteries  and  veins,  if  those  included  in  this  chapter  and  showing 
the  diseases  be  accepted  as  fair  types,  look  as  if  the  diseases  had 
attacked  the  blood-vessels  from  without.  They  are  surrounded  by 
infiltration  cells  and  their  outer  coats  are  infiltrated.  It  is  only 
in  the  smallest  and  thinnest-walled  vessels  that  the  infiltration  has 
extended  entirely  through  them,  or  that  the  cells  lie  within  the  lumen 
and  obstruct  it.  The  fact  that  vascular  disease  originates  some- 
times in  the  inner  and  sometimes  in  the  outer  coating  of  the  vessels 
is  one  of  the  most  striking  things  illustrated  by  the  blood-vessels 
which  are  depicted  in  this  chapter.  It  might  be  said  that  the  vas- 
cular disease  which  attacks  first  the  adventitia  of  the  larger  blood- 
vessels is  not  truly  a  primary  disease  of  the  blood-vessels,  for  it  at- 
tacks them  only  through  the  vasa  vasorum,  which  are  distributed 
through  the  adventitia,  or  by  a  process  of  extension  from  the  surround- 
ing tissues.  Such  an  objection  is  to  a  certain  extent  theoretically 
correct,  but  for  practical  purposes  it  may  be  assumed  that  vascular 
disease  does  arise  in  the  two  ways, — truly  from  within  in  endarteritis 
and  in  ulceration  of  the  lining,  and  from  without  when  such  lesions 


7 6  HUMAN  BLOOD-VESSELS 

are  produced  as  inflammation  and  tubercular  disease  of  the  blood- 
vessels. 

Another  curious  and  important  lesson  taught  by  such  blood- 
vessels as  those  depicted  by  the  drawings  in  this  chapter,  is  that  the 
three  diseases,  inflammation,  tuberculosis,  and  syphilis,  all  produce 
lesions  which  are  in  no  way  peculiar  to  them  nor  to  any  other  one 
disease.  Any  of  the  lesions  illustrated  may  be  produced  by  other 
diseases  besides  the  one  with  which  the  patient  from  whose  body  the 
specimen  was  obtained  was  suffering.  Inflammation  and  tuberculosis 
produce  lesions  which  are  histologically  identical,  and  the  lesions 
found  in  the  case  of  syphilis — and  I  have  found  identical  ones  in 
other  cases — are  those  which  are  common  to  all  sorts  of  diseases  in 
human  beings,  and  even  in  those  who  have  not  seemed  during  life  to 
be  diseased  at  all — for  instance,  in  persons  who  have  died  of  violent 
death,  having  been  previously  in  apparently  good  health.  My  own 
experience  in  the  examination  of  the  tissues  of  persons  who  were 
known  during  life  to  have  had  syphilis,  and  even  of  those  who  died  of 
its  direct  effects,  leads  me  to  think  that  syphilis  does  not  so  often 
cause  disease  of  the  blood-vessels  as  has  been  thought  by  some 
eminent  authorities. 


CHAPTER    VIII 
THE  BLOOD-VESSELS  OF  THE  HEART 

THE  heart  is  certainly  one  of  the  most  important  organs  of  the 
human  economy  if  it  is  not  the  most  important  of  them  all.  It  is 
therefore  hardly  necessary  to  say  that  it  is  impossible  to  know  its 
anatomy  too  thoroughly.  I  have  already  issued  various  publications 
upon  the  subject  of  the  blood-vessels  of  the  heart,  but  at  the  risk  of 
repetition  I  shall  try  to  describe  the  entire  course  of  the  cardiac  cir- 
culation as  far  as  it  is  known.  In  some  of  my  publications  previously 
issued,  it  was  asserted  that  the  arteries  and  veins  upon  the  surface  of 
the  heart  are  like  those  of  the  other  organs,  and  that  they  are  com- 
posed of  three  coats.  This  is  strictly  correct  as  far  as  concerns 
the  arteries,  and  almost  equally  so  in  regard  to  the  veins  ;  but  a  more 
extended  study  of  the  subject,  carried  out  since  my  last  publication 
was  issued,  has  made  me  think  it  necessary  to  modify  the  statement 
a  little.  The  veins  upon  the  surface  of  the  heart  do  indeed  ordina- 
rily have  three  coats, — intima,  muscularis,  and  adventitia, — but  some- 
times they  are  formed  of  a  single  coat,  and  the  tissue  composing  this 
coat  appears  to  be  fibrous,  and  no  muscle  cells  can  be  distinguished 
in  it.  Whether  this  results  from  disease  only  or  can  occur  also  in  the 
normal  heart  I  am  not  now  certain. 

The  sinus  venosus — which  is  the  terminal  vein  of  the  heart,  and  is 
therefore  the  largest  of  the  cardiac  veins — is  composed,  as  far  as  I 
have  been  able  to  discover,  of  fibrous  tissue  only  (see  Fig.  17).  This 
fibrous  tissue  is  directly  in  contact  with  the  cardiac  muscle.  The 
arterioles  of  the  heart  are  very  short  after  they  leave  its  surface  to 
penetrate  the  muscular  tissue,  breaking  up  almost  immediately  into 
capillaries.  The  capillaries  surround  the  muscular  fibres  in  every  con- 
ceivable way  and  run  in  all  directions  amongst  them — parallel  with 
them,  across  them  at  right  angles,  and  diagonally  at  all  possible  angles. 
The  number  of  the  capillaries  is  very  great,  showing  that  the  heart  is 
most  bountifully  supplied  with  blood.  The  capillaries  of  the  heart, 
however,  are  not  simply  distributed  around  the  muscular  fibres,  as  those 
of  the  kidney  surround  the  tubules,  but  they  actually  penetrate  the 

77 


78  HUMAN  BLOOD-VESSELS 

fibres.  The  fact  that  the  muscular  fibres  of  the  human  heart  are  pene- 
trated by  the  capillaries  is  striking  and  curious  and  there  is  no  such 
penetration  at  an  early  embryological  stage;  but  the  subject,  is  one 
that  I  have  already  discussed.1  Another  striking  feature  of  the  blood- 
vessels of  the  heart  is  the  existence  of  many  very  large  capillaries. 
These  are  so  large  and  so  numerous  and  of  such  curious  shapes  some- 
times that  it  would  seem  that  they  must  serve  as  reservoirs  besides 
being  carriers  of  blood,  resembling  in  this  respect  the  venous  sinuses 
of  the  placenta. 

In  a  study  like  this  of  the  blood-vessels  of  the  heart,  it  might  for 
some  reasons  be  best  not  to  attempt  to  discuss  the  subject  of  the 
structure  of  the  muscle.  On  the  other  hand,  the  blood-vessels  are 
so  intimately  related  to  the  muscular  tissue  that  it  is  impossible  to 
comprehend  their  minute  anatomy  without  knowing  something  of 
that  of  the  muscle.  The  involuntary  muscle  of  the  human  heart 
is  different  from  other  involuntary  muscle  and  is  different  from  vol- 
untary muscle  also,  but  heart  muscle  is  much  more  nearly  like 
voluntary  muscle  in  appearance  than  like  ordinary  involuntary 
muscle.  The  fibres  of  the  muscle  of  the  heart  are  branched,  and  it 
has  been  said  that  they  are  without  any  sheaths  like  the  sarcolemma 
of  the  voluntary  muscle.  The  appearance  of  the  cross  striae  which 
are  sometimes  so  very7  distinct,  and  of  the  longitudinal  markings,  which 
have  been  explained  as  being  due  to  the  division  of  the  fibres  into 
fibrillae,  are  well  known,  and  so  are  the  familiar  elongated  cells  with* 
nuclei  and  pointed  ends  of  common  involuntary  muscle.  When  one 
comes,  however,  to  consider  the  minute  structure  of  the  striped  volun- 
tary muscle  of  man,  or  of  the  lower  animals,  or  the  muscle  of  the  human 
heart,  it  must  be  confessed  that  there  is  not  much  known  about  it. 
It  is  not  yet  known  how  any  muscle  performs  its  function  of  contrac- 
tion, and  until  more  has  been  learned  of  this  important  physiological 
question  it  is  likely  that  it  will  continue  to  be  impossible  to  know  what 
the  structure  of  muscle  is. 

Various  theories  have  been  put  forth  to  explain  muscular  contrac- 
tion, but  no  one  of  them  has  as  yet  been  established.  There  cannot 
be  anything  incomprehensible  about  it,  and  probably  the  contraction 
of  muscle  is  caused  by  some  mechanical  principle  as  simple  in  its 

1  Origin  of  Disease,  by  Arthur  V.  Meigs,  second  edition,  page  65  :  J.  B.  Lippincott  Co., 
1899. 


THE  BLOOD-VESSELS  OF  THE  HEART  79 

nature  as  the  force  of  steam  pressure  or  that  which  is  derived  from 
the  descent  of  water  from  a  higher  to  a  lower  level.  The  sooner 
scientific  men  divest  themselves  of  the  belief  that  there  must  be  some- 
thing complicated  or  inexplicable  about  muscular  contraction  and 
search  for  a  simple  cause,  the  sooner  a  solution  of  the  problem  will 
be  found.  Within  a  few  years  it  has  been  suggested  that  muscular 
contraction  is  caused  by  the  movement  of  fluids.  That  by  the  pro- 
cess of  imbibition  .fluid  moves  from  around  certain  portions  of  muscle 
to  the  interior,  and  that  the  enlargement  of  the  muscle  caused  by  this 
imbibition  of  fluid  causes  the  muscle  to  shorten.  McDougal  has 
published  essays1  in  which  he  endeavors  to  prove  the  correctness  of 
the  imbibition  theory.  His  experiments  were  made  principally  with 
the  wing  muscles  of  insects,  and  his  conclusion  is  that  the  fibrillae  are 
the  units  of  contraction.  He  states  that  each  fibrilla  has  partitions 
across  it,  and  that  there  is  an  interfibrillar  fluid.  When  contraction 
takes  place  interfibrillar  fluid  passes  to  the  inside  of  each  one  of  the 
separate  spaces  of  the  fibrillae,  and  this  causes  widening  and  thereby 
contraction.  He  gives  an  interesting  demonstration  and  proves  by 
calculations  that,  if  the  fibrillae  of  muscle  have  a  certain  structure, 
contraction  may  take  place  in  the  manner  he  suggests.  Further  he 
says  that  he  has  seen  with  the  microscope  lateral  bulgings  upon  the 
sides  of  the  fibrillae  when  they  are  contracted.  These  lateral  bulg- 
ings have  been  seen  and  described  by  quite  a  number  of  different 
observers.  They  have  sometimes  been  called  waves  of  contraction. 

Edward  B.  Meigs  has  reached  conclusions  in  some  respects  similar 
from  studies  carried  out  principally  upon  the  voluntary  muscle  of  the 
frog,2  but  he  believes  that  the  unit  of  contraction  is  the  muscle  fibre 
and  that  in  the  frog  fibrillae  do  not  exist  as  they  are  commonly  de- 
scribed. This  conclusion  is  supported  by  mathematical  calculations 
demonstrating  that,  if  the  muscle  fibre  of  the  frog  has  the  structure 
that  he  predicates,  and  fluid  is  imbibed,  contraction  must  take  place. 

XW.  McDougal,  On  the  Structure  of  Cross- Striated  Muscle  and  a  Suggestion  as  to  the 
Nature  of  its  Contraction,  Journal  of  Anatomy  and  Physiology,  vol.  xxxi,  page  410,  1897; 
and  A  Theory  of  Muscular  Contraction,  Journal  of  Anatomy  and  Physiology,  vol.  xxxii. 
page  187,  1898. 

2  Edward  B.  Meigs,  On  the  Mechanism  of  the  Contraction  of  Voluntary  Muscle  of  the 
Frog,  American  Journal  of  the  Medical  Sciences,  April,  1904;  and  A  Mechanical  Theory 
of  Muscular  Contraction  and  some  New  Facts  Supporting  it,  American  Journal  of  Physi- 
ology, vol.  xiv.,  No.  ii,  page  138,  1905. 


8o  HUMAN  BLOOD-VESSELS 

There  is  a  description  with  illustrations  showing  that  the  appearance 
of  the  voluntary  muscle  of  the  frog  is  very  different  according  as  it  is 
examined  contracted  or  uncontracted.  Uncontracted  muscle  fibre 
presents  the  appearance  of  a  cylinder  with  straight  sides,  while  the 
same  fibre  when  contracted  has  bulgings  along  its  sides  which  make 
it  resemble  a  string  of  beads.  There  are  illustrations  to  show  that 
there  are  partitions  across  the  muscle  fibres  at  regular  intervals,  that 
the  outer  portions  or  sheaths  of  the  fibres  are  quite  different  in  struc- 
ture from  the  central  part,  and  that  the  peripheral  and  central  parts 
of  the  fibres  appear  very  different  according  as  the  muscle  is  examined 
contracted  or  uncontracted. 

The  opinions  of  the  one  observer  that  the  fibrillae  and  of  the  other 
that  the  fibres  are  the  contractile  units  are  not  necessarily  irrecon- 
cilable, for  it  may  be  that  what  are  called  the  fibrillse  of  the  wing 
muscles  of  insects,  and  which  are  capable  of  such  exceedingly  rapid 
contractions,  are  the  same  as  what  are  called  fibres  in  the  voluntary 
muscle  of  the  frog.  This  imbibition  hypothesis  for  the  explanation  of 
the  contraction  of  muscle  appeals  to  me  as  more  reasonable  than  any 
other  of  which  I  have  heard,  and  it  is  supported  by  strong  evidence. 
In  my  own  examinations  of  human  heart  muscle  I  have  found  many 
conditions  that  I  cannot  comprehend  if  the  commonly  accepted  belief 
that  the  fibres  are  regularly  divided  into  fibrillae  is  correct  It  is  in- 
variably the  case  that  the  central  parts  of  the  muscle  fibres  of  the 
human  heart,  especially  the  portions  of  the  centres  near  the  nuclei, 
differ  in  appearance  from  the  outer  parts.  It  has  been  said  that  the 
centres  are  more  or  less  hollowed  out,  which  is  a  way  simply  of  saying 
that  the  liquid  or  solid  substance  that  occupied  the  centres  of  the  fibres 
did  not  stain  like  the  outer  portions.  This  so-called  hollow  condition 
of  the  fibres  has  generally  been  attributed  to  disease,  but,  as  it  is  so 
invariably  present  in  human  heart,  I  have  long  been  disposed  to  believe 
it  to  be,  partly  at  least,  natural.  Such  an  appearance  as  that  of  Fig.  53 
in  my  book  on  the  "Origin  of  Disease,"  which  shows  human  heart 
muscle  that  is  hollow  in  the  centre  and  has  a  peripheral  part  or  sheath 
like  ordinary  human  heart  muscle,  seems  to  me  to  support  the  imbi- 
bition hypothesis  which  is  founded  upon  the  existence  of  a  great 
difference  between  the  peripheral  and  central  parts  of  the  muscular 
fibres. 

The  fact  that  there  is  a  difference  between  the  peripheral  and  central 


THE  BLOOD-VESSELS  OF  THE  HEART  81 

parts  of  the  muscular  fibres,  especially  of  those  of  the  human  heart,  has 
been  recognized  by  histologists.  For  instance,  Piersol,1  in  describing 
heart  muscle,  says,  "  The  peripheral  fibrillae  are  grouped  into  flat  ribbon- 
like  muscle-columns,  somewhat  radially  disposed  about  the  circumfer- 
ence of  the  fibre  ;  the  remaining  central  portion  is  occupied  by  prismatic 
bundles  of  fibrillae,  together  with  the  nuclei  and  the  associated  protoplasm 
(Ranvier,  Kolliker)."  This  shows  that  it  is  pretty  well  known  that 
there  is  a  difference  between  the  peripheral  and  central  portions  of  the 
fibres,  but  the  description  that  has  been  quoted  is  not  very  clear,  and  it 
betrays  the  fact  that,  while  it  has  been  reorganized  that  the  outer  and 
inner  portions  of  the  fibres  are  different,  the  nature  of  the  structure  of 
muscle  is  not  yet  known.  It  might  be  thought,  as  I  have  already  said, 
that  the  subject  of  the  minute  anatomy  of  the  heart  should  not  be  con- 
sidered in  a  study  of  the  cardiac  blood-vessels ;  but  it  is  impossible  to 
have  full  knowledge  of  the  blood-vessels  until  the  structure  of  the 
muscle  is  better  known  than  it  now  is,  and  it  is  most  probable  that 
the  next  step  in  advance  will  be  the  acquisition  of  an  understanding 
of  muscular  contraction  which  will  necessarily  bring  with  it  a  better 
knowledge  of  the  anatomy  of  the  muscular  fibres.  Everything  about 
anatomy  cannot  be  learned  from  embryology,  for  it  is  certain  that 
there  are  conditions  of  structure  which  are  post-embryonic  in  their 
development.  For  instance,  it  is  reasonably  certain,  from  what  is 
known  of  the  mode  of  development  of  muscle,  that  at  early  embryo- 
logical  periods  the  muscular  fibres  of  the  heart  are  not  penetrated  by 
the  capillaries,  but  I  believe  that  there  can  be  no  doubt  that  they  are  so 
penetrated  in  the  adult  man.  This  must  be  a  post-embryonic  develop- 
ment, and  the  only  reasonable  hypothesis  for  its  explanation  is  that  the 
capillaries  become  surrounded  by  a  process  of  inclusion — that  subse- 
quent to  birth  the  muscular  tissue  grows  around  the  capillaries.  The 
discovery  of  the  cause  of  muscular  contraction  is  almost  certain  to  throw 
light  upon  the  whole  subject,  and  many  of  the  already  ascertained  facts 
in  regard  to  the  structure  of  muscle  seem  to  me  to  point  to  the  prob- 
ability of  the  correctness  of  the  imbibition  hypothesis. 

The  illustrations  with  this  chapter  exhibit  the  peculiarities  of  the 
blood-vessels  of  the  heart  in  a  way  that  it  is  impossible  to  equal  by 
any  verbal  description.  Figs.  59,  60,  61,  and  62  are  four  drawings  of 

1  Normal  Histology,  by  George  A.  Piersol,  page  66  :    Philadelphia,  J.  B.  Lippincott  Co., 
1893. 
6 


82  HUMAN  BLOOD-VESSELS 

heart,  and  they  are  intended  to  show  the  most  striking  features  of  the 
minute  cardiac  blood-vessels  as  they  enter  the  muscular  tissue,  ramify 
in  it,  and  come  out  from  it.  It  is  the  heart  of  a  negro  woman  forty 
years  old  who  died  from  the  effects  of  burns.  Some  pieces  of  the  or- 
gan were  preserved  in  Flemming's  solution,  and  others  in  seventy  per 
cent,  alcohol,  and  they  were  stained  in  bulk  with  borax-carmine  and 
embedded  in  paraffin.  Fig.  59  is  a  terminal  arteriole  in  the  muscu- 
lar tissue.  It  shows  the  branching  of  the  arteriole  and  the  change 
into  capillaries.  This  conversion  is  effected  by  the  disappearance  of 
the  adventitia  and  of  the  muscular  tissue.  At  one  of  its  ends  the  ves- 
sel is  a  minute  artery  with  three  coats,  and  at  the  other  it  has  divided 
into  capillaries  consisting  of  a  single  layer  of  endothelium.  Between 
these  two  extremes  is  seen  the  gradual  disappearance  of  the  adventitia 
and  muscularis.  Scattered  muscular  fibres  both  of  the  longitudinal  and 
of  the  circular  layers  and  how  these  become  more  and  more  sparse 
are  well  shown  by  the  drawing.  The  manner  in  which  arteries  divide 
and  subdivide  to  form  capillaries  is  perfectly  well  known,  but  it  has 
not  been  well  shown  by  illustrations  so  often  as  to  make  this  one  of 
mine  seem  trite. 

Fig.  60  illustrates  muscular  fibre  in  cross-section.  It  shows  the 
capillaries  in  various  situations.  They  are  seen  in  the  intermuscu- 
lar  spaces  and  in  the  fibres  themselves,  so  that  they  are  completely 
surrounded  by  muscle.  Some  of  the  capillaries  within  the  fibres  are 
simply  rings  of  endothelium  (b  and  d\  and  others  (a  and  c]  are  com- 
posed of  endothelium  with  a  nucleus  at  one  side,  producing  an  appear- 
ance somewhat  like  that  of  a  seal  ring.  This  drawing  has  been  so 
carefully  elaborated  that  the  peculiarities  of  the  appearance  of  the 
muscular  tissue  and  of  the  capillaries  can  be  even  better  distinguished 
if  it  is  examined  with  a  magnifying  glass. 

Fig.  6 1  shows  heart  muscle  fibre  cut  longitudinally.  At  one  side  a 
group  of  capillaries  is  seen  entering  the  muscle  to  be  distributed 
among  the  fibres.  It  is  a  good  illustration  of  the  great  number  of  the 
capillaries  and  of  the  manner  in  which  they  pass  between  and  around 
the  fibres.  In  this  case  no  capillaries  can  be  distinguished  within  the 
fibres,  but  it  is  always  more  difficult  to  see  capillaries  within  the  fibres 
in  longitudinal  sections  than  when  the  muscle  is  cut  across. 

Fig.  62  is  reproduced  from  a  drawing  of  a  large  capillary.  It  is 
impossible  to  be  certain  whether  any  one  particular  large  capillary  like 


FIG.  59. — TERMINAL  ARTERIOLE  OF  HEART.     (X  55.) 

From  a  woman  forty  years  old  who  died  of  burns.  Most  of  the  muscular  fibres  are  cut 
longitudinally.  The  arteriole  is  branched  and  it  extends  across  an  intermuscular  space.  To 
the  right  it  presents  the  common  appearances  of  an  arteriole ;  the  involuntary  muscular  tissue 
is  easily  distinguished.  To  the  left  the  small  terminal  branches  are  capillaries.  The 
manner  in  which  arterioles  break  up  into  capillaries  is  very  well  shown.  The  two  outer 
coatings — adventitia  and  muscularis — become  thinner  and  thinner  until  they  disappear  and 
only  the  intima  remains,  which  is  the  endothelium,  and  it  forms  the  wall  of  the  capillary. 

FIG.  60. — HEART  CAPILLARIES.     (X  260.) 

From  the  same  case  as  Fig.  59.  The  muscular  fibres  and  the  capillaries  are  cut  across. 
The  fibres  are  of  very  irregular  shapes.  The  capillaries  are  in  the  spaces  between  the 
fibres  and  in  the  fibres,  some  capillaries  being  in  the  very  centres  of  fibres,  a,  a  capil- 
lary in  the  centre  of  a  fibre.  Its  endothelial  wall  is  distinctly  shown,  and  upon  one  side  the 
nucleus  has  been  cut  through,  and  as  this  makes  a  thickening  upon  one  side  it  gives  the  capil- 
lary the  appearance  of  a  seal-ring,  b,  a  capillary  in  the  centre  of  a  fibre, — it  is  a  delicate 
ring  of  endothelium  which  is  nearly  circular,  c,  a  capillary  in  a  space  between  fibres.  A 
nucleus  was  cut  through  and  the  capillary  therefore  looks  like  a  seal-ring,  d,  a  capillary 
between  fibres.  It  is  a  delicate  circle  of  endothelium. 


FIG.  61. — HEART  CAPILLARIES.     (X  260.) 

From  the  same  case  as  Fig.  59.  The  muscular  fibres  and  the  capillaries  are  cut  longitu- 
dinally. To  the  right  a  number  of  capillaries  are  seen  entering  the  heart-muscle.  They 
pass  in  among  the  fibres  and  in  some  places  they  can  be  seen  crossing  the  fibres  at  various 
angles,  and  again  they  are  shown  between  fibres  and  parallel  with  them. 

FIG.  62. — LARGE  RETURN  CAPILLARY  OF  THE  HEART.     (X  55.) 

From  the  same  case  as  Fig.  59.  The  muscular  tissue  is  cut  longitudinally.  The  greater 
part  of  the  large  return  capillary  lies  in  an  intermuscular  space.  A  number  of  branches, 
some  of  which  are  seen  to  be  coming  out  of  the  muscular  tissue,  join  to  form  the  main  tube. 
The  walls  of  all  of  these  vessels  are  composed  of  endothelium,  although  the  largest  one  is  of 
greater  size  than  the  arteriole  shown  by  Fig.  59.  The  venous  radicles  in  the  muscle  of  the 
heart  are  almost  all  of  this  nature,  and  it  is  unusual  to  find  a  vein  with  three  coats  anywhere 
in  the  heart  except  upon  the  surface. 


^100  mm- 


Fis.60 


fig.  6  2 


THE  BLOOD-VESSELS  OF  THE  HEART  83 

this  was  afferent  or  efferent  in  its  function,  or  if  it  was  of  the  nature  of 
a  sinus.  The  fact,  however,  that  after  death  such  vessels  are  much 
more  frequently  found  to  be  filled  with  blood-corpuscles  than  the 
arterioles  are,  and  that  practically  there  are  no  veins  within  the  mus- 
cular tissue  of  the  heart,  makes  it  certain  that  some  of  the  large  capil- 
laries are  efferent  in  function  and  do  the  work  of  veins.  The  blood- 
vessel which  is  here  depicted  I  believe  to  be  a  good  type  of  this 
class.  It  may  be  thought  strange  perhaps  that  in  a  plate  like  this, 
which  represents  heart  muscle,  no  attempt  has  been  made  to  show  the 
cross  striae  which  are  commonly  supposed  to  be  among  the  most 
striking  features  of  the  appearance  of  heart  muscle,  as  indeed  they  are. 
The  cross  striae  of  muscle,  and  especially  of  human  heart  muscle,  are 
however,  by  no  means  so  easy  to  see  as  is  commonly  supposed,  and 
they  are  very  difficult  to  depict.  It  is  commonly  the  case  that  in  such 
human  heart  muscle  as  can  be  obtained  for  microscopical  examination 
the  cross  striae  cannot  be  seen  at  all,  and  the  fibres  have  instead  a 
rather  granular  appearance.  Cross  striae  can  be  seen  in  places  in  the 
muscle  depicted  by  the  plate,  but  only  in  small  areas  and  by  careful 
focussing  of  the  microscope,  and  the  muscle,  if  its  general  effect  be 
considered,  has  much  more  nearly  the  appearance  which  is  shown  by 
the  drawings  than  would  have  been  produced  if  lines  had  been  drawn 
across  the  fibres  to  represent  the  cross  striae. 

This  plate  gives  an  excellent  general  idea  of  the  cardiac  circulation 
in  the  muscular  substance  of  the  heart.  The  blood  enters  by  arterioles 
and  is  distributed  by  capillaries,  which  exist  in  vast  numbers,  among 
and  around  the  muscular  fibres  and  even  in  their  very  centres.  It 
then  comes  out  through  large  capillaries  which  perform  the  function 
which  is  carried  on  by  minute  veins  in  other  organs. 

Fig.  63  represents  the  heart  of  a  man  thirty  years  old  who  died 
of  lead  encephalopathy.  At  the  time  the  autopsy  was  made  the 
arteries  were  injected  with  a  solution  of  Berlin  blue,  and  afterwards 
the  tissue  was  stained  in  bulk  with  borax-carmine  and  embedded  in 
paraffin.  The  injected  material  passed  into  the  capillaries,  and  the 
illustration,  which  was  made  with  the  camera  lucida  and  drawn  ac- 
curately to  scale,  shows  that  the  vascular  supply  of  the  heart  is  very 
rich.  It  must  be  remembered  that  it  is  most  unlikely  that  even  half 
of  the  capillaries  are  filled  with  the  blue  injection  material.  The 
drawing  shows  many  capillaries  that  appear  to  cease  abruptly,  and 


84  HUMAN  BLOOD-VESSELS 

there  are  spots  that  are  entirely  uninjected.  It  is  reasonable,  there- 
fore, to  believe  that  my  estimate  that  more  than  half  of  the  capillaries 
are  uninjected  is  not  exaggerated.  The  number  of  capillaries  in  the 
heart,  therefore,  is  even  greater  than  this  drawing  would  lead  one  to 
suppose ;  but  upon  the  whole  it  gives  an  excellent  general  idea  of  the 
capillaries  of  the  human  heart. 

Fig.  64  is  from  the  heart  of  a  man  sixty  years  old  who  died  of  endo- 
carditis and  cardiac  dilatation.  It  was  injected  and  prepared  exactly 
as  was  Fig.  63.  The  muscular  fibres  are  cut  longitudinally,  and  in  one 
of  them  there  is  an  injected  capillary  running  directly  in  the  centre 
of  the  fibre  which  is  most  graphically  shown.  In  other  respects  the 
illustration  shows  the  ordinary  appearances  of  cardiac  muscular  fibre 
and  the  relations  of  the  capillaries  to  them.  The  capillaries  are  colored 
blue  and  can  be  seen  branching  in  various  directions.  Most  of  them 
lie  between  the  fibres. 

Fig.  65  depicts  the  heart  of  a  man  forty-six  years  old  who  died  of 
tuberculosis.  This  heart  was  injected  and  prepared  in  the  same 
manner  as  the  one  represented  by  Fig.  63.  The  muscular  fibre  is  cut 
across  and  most  of  the  capillaries  are  seen  in  cross-section,  although 
a  few,  especially  some  of  the  larger  ones  which  are  entering  from  the 
pericardium,  are  cut  lengthwise.  Most  of  them  are  in  the  intermus- 
cular  spaces,  but  quite  a  number  are  more  or  less  completely  within 
the  muscular  fibres.  Two  capillaries  (cT)  lie  completely  within  a  fibre. 
These  two  capillaries  are  not  completely  filled  by  the  blue  injection 
which  must  have  passed  through  them  and  tinted  them  ;  they  demon- 
strate, therefore,  unusually  well  that  the  capillaries  penetrate  to  the 
centres  of  the  fibres.  Their  endothelial  walls  and  the  nuclei  to  one 
side  can  be  easily  distinguished.  Injected  preparations  are  not  gener- 
ally the  best  in  which  to  study  fine  points  in  histology,  for  the  injection 
material  usually  fills  the  capillaries  full  and  the  mass  of  color  obscures 
the  vessel-walls  so  that  only  the  situations  and  not  the  characteristics 
of  the  capillaries  can  be  seen.  In  this  case  the  injection  passed  into 
the  vessels  and  stained  them  delicately,  but  they  are  not  filled  and 
their  walls  can  therefore  be  distinctly  seen. 

Fig.  66  shows  a  capillary  of  the  heart  of  a  woman  forty- two  years  old 
who  died  of  cerebral  apoplexy.  The  shape  is  very  curious  and  there 
cannot  be  any  doubt  that  it  is  a  capillary,  for  the  appearance  of  the 
wall  is  perfectly  characteristic  and  the  interior  is  partly  filled  with 


FIG.  63. — INJECTED  BLOOD-VESSELS  OF  HEART.     (X  55.) 

From  a  man  thirty  years  old  who  died  of  lead  encephalopathy.  The  heart-muscle  is  cut 
longitudinally  and  it  is  stained  red.  The  blood-vessels  are  blue,  and  it  is  seen  that  they  are 
very  numerous,  although  it  is  almost  certain  that  only  a  small  proportion  of  the  total  number 
of  them  show,  for  it  is  reasonably  sure  that  the  blue  injection  material  failed  to  fill  them  all. 
The  supply  of  blood  to  the  heart  is  very  bountiful. 

FIG.  64. — INJECTED  CAPILLARIES  WITHIN  THE  MUSCULAR  FIBRES  OF  THE  HEART. 

(X  260.) 

From  a  man  sixty  years  old  who  died  of  endocarditis  and  cardiac  dilatation.  The  mus- 
cular fibre  is  cut  longitudinally.  It  is  red  and  the  injected  capillaries  are  blue.  They  lie 
between  the  fibres  and  within  them.  In  the  middle  portion  of  the  drawing  is  a  broad  fibre, 
and  in  its  very  centre  is  an  injected  capillary. 

FIG.  65. — INJECTED  CAPILLARIES  WITHIN  THE  MUSCULAR  FIBRES  OF  THE  HEART. 

(X  260. ) 

From  a  man  of  forty-six  years  who  died  of  tuberculosis.  The  muscular  fibre  is  cut 
across.  It  is  stained  red  and  the  injected  capillaries  are  blue.  The  fibres  are  of  irregular 
shapes  and  of  varying  sizes.  The  section  includes  a  portion  of  pericardium  and  there  are 
two  good-sized  blood-vessels  extending  from  it  into  the  muscular  tissue.  These  were  cut 
longitudinally.  Most  of  the  capillaries  were  cut  across  and  lie  between  the  muscle-fibres  and 
within  them.  d  shows  two  capillaries  within  muscular  fibre.  They  were  cut  across  and  a 
nucleus  is  seen  in  each  of  the  capillaries,  which  makes  them  look  like  seal-rings.  The  in- 
jection did  not  fill  these  capillaries  and  they  are  only  slightly  tinted  blue.  In  consequence 
of  this  the  structure  of  the  vessel  walls  and  the  nuclei  can  be  better  seen  than  in  most 
injected  blood-vessels,  for  heavy  injections  obscure  the  tissues. 


FIG.  63. 


FH;.  64. 


THE  BLOOD-VESSELS  OF  THE  HEART  85 

blood-corpuscles.  There  is  no  reason  to  suppose  that  this  blood- 
vessel is  abnormal,  and  if  it  is  not  it  must  have  fulfilled  the  function 
of  a  reservoir  rather  than  of  a  mere  carrier  of  blood,  for  if  its  only  use 
had  been  to  transport  blood  it  would  not  have  been  of  such  great 
diameter  when  the  entering  tube  is  so  small.  This  exemplifies  a 
curious  and,  as  far  as  I  know,  not  commonly  described  phase  of  the 
cardiac  circulation. 

Fig.  67  is  a  group  01  capillaries  of  the  heart  of  a  negro  woman 
twenty-eight  years  old  who  died  of  catarrhal  pneumonia.  It  shows 
how  very  numerous  capillaries  are  in  the  heart,  and  there  is  no  reason 
to  suppose  that  these  are  an  abnormal  production.  The  muscular 
fibres,  however,  are  separated  in  a  manner  that  is  probably  abnormal. 
This  may  be  due  to  the  growth  of  fibroid  tissue,  or  there  may  have 
been  oedema,  the  exudation  causing  separation  of  the  fibres.  The 
group  of  capillaries  affords  a  striking  example  of  how  very  vascular 
the  heart  is. 

In  Fig.  68  is  seen  a  group  of  blood-vessels  consisting  of  an  artery  and 
two  veins  of  the  surface  of  the  heart  of  a  man  forty-six  years  old  who 
died  of  pulmonary  phthisis.  The  vessels  lie  in  the  fat  upon  the  surface 
of  the  heart  No  one  of  these  blood-vessels  is  normal.  The  wall  of 
the  artery  is  thickened  more  at  some  parts  of  its  circumference  than  at 
others.  The  intima  is  relatively  much  more  thickened  than  either  of 
the  other  coats.  The  veins  are  quite  unlike  the  accepted  histological 
standards.  Their  walls  are  of  irregular  thickness  and  are  formed  of 
loose-meshed  tissue  composed  of  involuntary  muscle  and  connective 
tissue.  There  is  no  distinct  separation  into  three  coats.  As  already 
said,  it  is  very  difficult  to  find  blood-vessels  which  are  typically  normal 
according  to  the  accepted  standards  of  anatomy.  Embryologists 
have  elaborately  studied  the  development  of  the  blood-vessels  in  many 
of  the  lower  animals,  and  to  a  great  extent  in  man,  and  an  accepted 
and  correct  standard  of  the  normal  has  been  attained  ;  but  the  study 
of  human  tissues  obtained  post  mortem  from  the  bodies  of  persons, 
almost  all  of  whom  have  died  of  disease,  shows  that  it  is  rare  to  find 
blood-vessels  that  are  absolutely  normal.  The  condition  of  these 
three  vessels  is  fairly  typical  of  what  it  is  common  to  find  in  the 
hearts  of  persons  dead  of  almost  every  known  disease.  In  the  heart 
it  is  common  to  find  the  intima  of  the  arteries  greatly  thickened,  and 
the  veins  upon  the  surface  are  often  composed  of  loose-meshed  tissue 


86  HUMAN  BLOOD-VESSELS 

and  without  any  distinct  division  into  three  coats.  In  order  to  see 
the  more  minute  details  of  such  disease  it  is  necessary  to  use  greater 
amplification,  but  the  drawing  gives  a  good  general  idea  of  the  con- 
dition. 

Fig.  69  is  an  illustration  of  an  artery  of  the  surface  of  the  heart  of 
a  negro  infant  one  year  old  who  died  of  chronic  catarrhal  pneumonia. 
It  shows  that  even  at  so  early  an  age  the  intima  may  not  be  simply 
a  layer  of  endothelium  lying  inside  the  plicated  membrane.  At  the 
lower  portion  in  the  picture  the  intima  is  cellular  and  it  is  slightly 
thickened,  and  the  plicated  membrane  at  this  point  is  almost  indis- 
tinguishable. This  I  believe  to  be  the  earliest  form  of  disease  of 
this  nature.  The  subject  has  already  been  discussed  in  my  book 
on  the  "Origin  of  Disease  "  (page  43).  Fig.  70  depicts  an  artery  of 
the  surface  of  the  heart  of  a  boy  two  years  old  who  died  of  nephritis. 
It  shows  disease  of  the  same  nature  as  that  seen  in  Fig.  69,  but  very 
much  more  extensive.  The  adventitia  shades  into  the  surrounding 
fibre-fatty  tissue  so  that  its  boundaries  cannot  be  distinguished.  The 
muscular  coat  is  of  varying  thickness  at  different  parts  of  the  artery, 
and  this  must  be  due  to  disease.  The  plicated  membrane  is  sharply 
outlined  and  is  easily  seen  at  most  places,  but  at  some  parts  of  the 
circuit  it  disappears  into  the  intima,  which  is  everywhere  thicker  than 
normal  and  is  irregularly  thick.  A  more  typical  example  of  the  con- 
dition commonly  found  in  the  arteries  of  the  human  hearts  obtained 
post  mortem,  it  would  be  difficult  to  discover.  It  is  rare  to  come 
across  an  artery  that  answers  the  ordinary  descriptions  of  the  normal, 
and  very  common  to  find  vessels  like  this  one.  It  is  almost  certain, 
therefore,  that  the  normal  type  is  seldom  to  be  found  long  after  birth. 
I  do  not  think  I  shall  exaggerate  in  saying  that  it  is  not  generally 
known  that  the  arteries  are  often  like  this  even  at  so  early  a  period 
of  life. 

Figs.  71  and  72  show  blood-vessels  of  the  heart  of  a  woman  forty- 
seven  years  old  who  died  of  obstruction  of  the  bowel.  They  lie  very 
close  together  in  the  tissue.  Fig.  7 1  is  probably  an  efferent  vessel  of 
the  character  which  has  already  been  described  (Fig.  62).  It  is  not 
exactly  like  the  ordinary  small  capillaries,  for  it  is  thicker  walled,  not 
being  composed  of  a  single  layer  of  endothelium,  and  it  contains  more 
cells  than  are  ordinarily  present  in  the  walls  of  capillaries.  It  is  prob- 
ably a  fair  type  of  the  kind  of  vessels  that  take  the  place  of  veins  in 


FIG.  66. — NORMAL  LARGE  CAPILLARY  OF  THE  HEART.     (X  105.) 

From  a  woman  forty-two  years  old  who  died  of  cerebral  apoplexy.  The  capillary 
resembles  a  wine-flask  with  a  narrow  neck.  Blood-corpuscles  lie  within  it.  Below,  to  the 
left,  and  above,  the  capillary  wall  containing  endothelial  nuclei  is  distinct.  To  the  right 
there  is  no  capillary  wall  visible.  At  the  top  the  capillary  divides  into  two  branches. 

FIG.  67. — NORMAL  CAPILLARY  NET  OF  HEART.     (X  240.) 

From  the  heart  of  a  negro  woman  twenty-eight  years  old  who  died  of  catarrhal  pneu- 
monia. The  capillaries  are  easily  recognized.  A  good  many  of  them  contain  blood- 
corpuscles.  The  muscular  fibres  are  somewhat  widely  separated, — this  was  probably  caused 
by  the  deposit  of  fibrous  tissue  or  by  oedema  of  the  heart. 


FIG.  66. 


FIG.  67. 


FIG.  68. — THICKENED  ARTERY  AND  DISEASED  VEINS  OF  THE  HEART.     (X  8.) 

From  a  man  forty-six  years  old  who  died  of  phthisis.  An  artery  and  two  veins  in  the 
fat  on  the  surface  of  the  heart.  The  artery  lies  between  the  two  veins.  Its  walls  are 
thickened,  especially  the  intima.  The  veins  are  quite  unlike  the  accepted  histological 
standards,  for  their  walls  are  principally  made  up  of  a  loose-meshed  tissue  composed  of 
involuntary  muscle  and  connective  tissue,  and  there  is  no  distinct  separation  into  three 
coats.  Such  disease  of  arteries  and  veins  is  common  in  those  who  have  had  chronic  disease 
and  in  persons  past  middle  life. 


FIG. 


FIG.  69. — ARTERY  OF  THE  HEART;  NEARLY  NORMAL.     (X  50.) 

From  a  negro  infant  one  year  old  who  died  of  chronic  catarrhal  pneumonia.  The  artery 
is  nearly  normal.  The  intima  is  a  little  thick  and  the  plicated  membrane  indistinguishable 
at  the  lowest  part. 

FIG.  70. — DISEASED  ARTERY  OF  THE  HEART.     (X  50.) 

From  a  boy  two  years  old  who  died  of  nephritis.  The  artery  lies  upon  the  surface  of 
the  heart,  and  at  so  early  a  period  of  life  the  heart  has  very  little  fat  upon  it.  The  muscu- 
lar coat  is  of  different  degrees  of  thickness  at  different  parts  of  its  circuit.  The  plicated 
membrane  is  distinguishable  around  most  of  the  artery,  but  not  all.  The  intima  is  thick- 
ened, showing  that  this  condition,  which  is  almost  universal  in  older  people,  may  occur  in 
early  life. 


FIG.  69. 


FIG.  70. 


FIG.  71. — NORMAL  BLOOD-VESSEL  FROM  HEART.     (X  105.) 

From  a  woman  forty-seven  years  old  who  died  of  obstruction  of  the  bowel.  Blood- 
vessels like  this  are  generally  found  in  human  heart.  This  vessel  has  not  the  characteristics  of 
arteries  or  veins,  nor  is  it  exactly  like  the  accepted  descriptions  of  capillaries,  for  it  is  thicker- 
walled.  The  wall  is  not  composed  of  a  single  layer  of  endothelium,  for  it  contains  more 
than  one  fibrous  layer  and  quite  a  good  many  cells  which  do  not  answer  the  description  of 
endothelial  cells.  The  vessel  has  some  small  normal  capillaries  around  it,  and  muscular 
fibres,  most  of  which  have  been  cut  across. 

FIG.  72. — DISEASED  BLOOD-VESSEL  OF  THE  HEART.     (X  105.) 

From  the  same  case  as  Fig.  71.  The  vessel  is  probably  a  vein.  The  walls  are  thickened 
so  that  the  tissue  hangs  in  festoons  in  the  lumen.  This  tissue  is  rich  in  cells  and  looks  much 
more  like  epithelium  than  like  the  ordinary  tissue  of  blood-vessel  walls. 


FIG.  71. 


•- 


FIG.  72. 


THE  BLOOD-VESSELS  OF  THE  HEART  87 

the  substance  of  the  heart.  Fig.  72  is  probably  a  vein.  The  muscu- 
laris  is  loose-meshed  and  it  is  like  that  shown  by  Fig.  34,  and  inside 
this  is  a  tissue  which  is  unlike  any  of  the  material  which  forms  normal 
blood-vessels.  It  is  more  like  epithelium  than  like  any  ordinary  vas- 
cular tissue.  I  have  already  described  somewhat  similar  growths  in 
blood-vessels. 

Fig.  73  shows  a  vein  of  the  surface  of  the  heart  of  a  man  twenty- 
seven  years  old  who  died  of  acute  cholera  morbus.  There  is  extensive 
blood  infiltration  and  many  of  the  fat-cells  of  the  fatty  covering  of 
the  heart,  in  which  the  vein  is  situated,  are  filled  with  blood-corpuscles 
which  had  exuded  from  the  vascular  channels.  These  show  dis- 
tinctly under  greater  amplification.  The  wall  of  the  vein  is  greatly 
thickened  and  this  thickening  is  of  very  irregular  distribution,  being 
much  greater  in  some  places  than  in  others.  The  thickening  seems 
to  be  principally  of  the  intima,  which  is  unusual  in  veins  although 
common  in  arteries.  Altogether  the  condition  of  disease  is  a  difficult 
one  to  explain,  for  it  is  not  common  in  my  experience  to  find  veins 
like  this,  and  besides  it  is  almost  necessary  to  believe  that  the  disease 
must  have  been  a  chronic  and  latent  one  which  preceded  the  acute 
attack  of  cholera  morbus  of  which  the  man  died  and  which  lasted 
only  twenty-four  hours.  To  the  fact  that  latent  chronic  disease  is 
common  in  persons  supposed  to  be  healthy  and  who  die  of  acute 
attacks,  I  have  frequently  alluded.  Fig.  74  shows  a  vein  upon  the 
surface  of  the  heart  of  a  woman  twenty-five  years  old  who  died  of 
puerperal  septicaemia.  It  can  hardly  be  thought  that  this  vein  is 
normal,  and  yet  it  is  difficult  to  say  exactly  what  has  affected  it.  It  is 
thicker  walled  than  normal  and  there  is  no  division  into  three  coats, 
the  greater  part  of  the  tissue  composing  it  seeming  to  be  fibrous. 
The  artery  accompanying  this  vein  is  greatly  diseased  and  its  intima 
is  very  much  thickened.  It  is  likely  that  in  the  case  of  this  vein,  as 
well  as  in  that  of  Fig.  73,  there  was  latent  chronic  disease  which  pre- 
ceded the  final  fatal  attack  which  was  of  short  duration.  Fig.  75 
depicts  another  vein  and  an  artery  of  the  surface  of  the  heart  of  the 
man  from  whom  the  vein  shown  by  Fig.  73  was  obtained.  The  vein 
is  thicker  walled  than  the  artery  and  there  is  no  differentiation  into 
three  coats.  The  condition  is  certainly  one  of  disease,  but  it  is  im- 
possible at  present  to  give  an  exact  explanation  of  it.  Perhaps  the 
blood  effusion  in  the  fatty  covering  of  the  heart,  which  was  so  exten- 


88  HUMAN  BLOOD-VESSELS 

sive  in  the  case  and  which  is  shown  by  the  drawing,  may  have  caused 
something  of  the  nature  of  oedema  of  the  wall  of  the  vein.  The 
accompanying  artery  is  not  affected  in  a  corresponding  manner,  but 
the  tissue  of  arteries  is  much  denser  than  that  of  veins,  and,  being 
composed  of  material  of  looser  texture  than  arteries,  the  veins  are 
probably  more  liable  to  become  swollen  and  unnatural  in  appearance. 

It  may  be  well  to  sum  up  some  of  the  more  important  points 
touching  the  blood-vessels  of  the  heart  that  have  been  under  consid- 
eration. It  is  almost  certain  that,  with  the  acquisition  of  knowledge 
of  the  nature  of  the  force  that  causes  the  contraction  of  muscle,  there 
must  come  an  advance  in  knowledge  of  the  minute  anatomy  of  mus- 
cular fibre,  and  therewith  a  corresponding  advance  in  knowledge  of 
the  capillaries  of  the  heart  and  of  their  distribution.  What  has  been 
said  in  this  chapter  shows  that  it  may  be  hoped  that  something  will 
soon  be  learned  regarding  the  cause  of  muscular  contraction,  and 
enough  has  been  said  to  show  that  the  belief  which  is  so  prevalent, 
that  muscular  fibre  is  a  nearly  homogeneous  substance,  is  far  from 
being  correct.  Histologists  know  that  there  is  a  great  difference  be- 
tween the  peripheral  and  central  parts  of  the  fibres. 

The  blood-vessels  of  the  heart  have  striking  peculiarities  of  their 
own,  and  are  in  several  ways  different  from  those  of  the  other  organs. 
The  illustration  of  a  terminal  arteriole,  and  of  its  breaking  up  into 
capillaries,  is  interesting.  Not  many  illustrations  of  vessels  like  this 
are  to  be  found  in  books,  although  there  must  be  thousands  of  such 
vessels  in  all  human  beings.  It  has  been  shown  that  the  accompanying 
venous  radicles  of  the  small  arterioles  of  the  heart  sometimes  have  the 
structure  of  large  capillaries,  and  one  of  the  illustrations  shows  that 
the  venous  capillaries  are  sometimes  so  large  as  to  make  it  likely  that 
they  must  have  something  of  the  function  of  reservoirs  like  sinuses. 
The  fact  that  minute  arterioles  are  accompanied  by  large  capillaries 
instead  of  by  veins  is  known  by  anatomists  to  be  the  arrangement 
in  various  parts  of  the  body,  but  it  is  not  as  generally  understood  as  it 
should  be.  The  penetration  of  the  muscular  fibres  of  the  heart  by 
the  capillaries  is  an  anatomical  peculiarity  that  I  have  dwelt  upon 
much.  What  is  known  of  embryology  seems  to  prove  that  there  can- 
not be  any  capillaries  within  the  fibres  during  the  earlier  stages  of 
development  of  muscle,  and  there  is  at  present  but  little  known  of  post- 
natal development.  The  discovery  of  the  capillaries  within  the  muscu- 


FIG.  73. — DISEASED  VEIN  OF  HEART.     (X  50.) 

From  a  man  twenty-seven  years  old  who  died  of  cholera  morbus.  A  vein  in  the  fat  upon 
the  surface  of  the  heart.  Extensive  infiltration  of  blood  into  the  fat  had  occurred  and  many 
of  the  fat-cells  around  the  vein  are  seen  to  be  full  of  red  blood-corpuscles.  The  vein  itself 
has  greatly  thickened  walls,  and  this  thickening  is  very  irregular,  being  twice  as  great  above 
as  it  is  below.  The  wall  is  thrown  into  folds,  which  is  due  to  post-mortem  shrinkage.  The 
thickening  of  this  vein  is  of  rather  unusual  nature, — it  looks  as  if  there  was  great  increase  of 
the  intima,  which  is  common  in  arteries  but  not  in  veins. 


FIG.  73. 


FIG.  74. — VEIN  OF  THE  HEART.     (X  50.) 

From  a  woman  twenty- five  years  old  who  died  of  puerperal  septicaemia.  The  vein  is  in 
the  fat  upon  the  surface  of  the  heart.  It  is  diseased,  for  the  wall  is  thicker  than  natural 
and  there  is  no  division  into  three  coats,  and  no  tissue  which  is  distinctly  muscular.  The 
artery  accompanying  this  vein  is  quite  extensively  diseased,  the  intima  being  very  much 
thickened. 

FIG.  75. — ARTERY  AND  DISEASED  VEIN  OF  THE  HEART.     (X  50.) 

From  a  man  twenty-seven  years  old  who  died  of  cholera  morbus.  The  artery  is  below 
and  the  vein  above  it ;  they  both  lie  in  the  fat  with  which  the  heart  is  covered.  There  is 
extensive  infiltration  of  the  fat  with  blood ;  this  is  so  great  that  many  of  the  fat  spaces  are 
filled  with  red  blood-corpuscles.  The  vein  (the  upper  vessel)  is  quite  unlike  the  accepted 
standards  of  the  normal.  Its  walls  are  thicker  than  those  of  the  artery,  and  there  is  no 
distinction  into  three  coats.  It  is  somewhat  like  Fig.  34  and  other  veins  diseased  in  the 
same  way. 


FIG.  74. 


FIG.  75. 


THE  BLOOD-VESSELS  OF  THE  HEART  89 

lar  fibres  of  the  heart  is  as  yet  inconclusive,  but  I  do  not  think  there 
can  be  any  reasonable  doubt  of  the  fact.  Nothing  can  now  be  said  of 
its  cause  except  that  it  is  probably  the  result  of  a  process  of  inclusion, 
the  fibres  growing  around  the  capillaries  after  birth,  or  possibly  the 
development  takes  place  during  the  latter  parts  of  the  intra-uterine 
period. 

The  injected  specimens  of  heart  of  which  colored  illustrations  are 
included  in  this  chapter  make  a  beautiful  and  most  graphic  demonstra- 
tion of  the  capillaries  within  the  muscular  fibres.  I  was  many  times 
urged  to  make  injections  of  the  heart  to  show  the  distribution  of  the 
capillaries,  and  the  injected  preparations  are  very  pretty,  and  they 
make  it  easy  to  see  the  capillaries  within  the  fibres,  but  they  do  not 
show  anything  that  I  had  not  already  seen  in  uninjected  specimens. 
Their  only  use,  therefore,  is  to  make  more  easy  of  demonstration  that 
which  was  perfectly  recognized  without  them. 

It  is  singular  to  find  that  in  infants  and  young  children  the  intima  of 
the  arteries  of  the  heart  is  sometimes  thicker  than  the  accepted  histo- 
logical  standards  teach  to  be  normal,  and  of  different  structure.  As 
I  have  so  many  times  said,  it  is  unusual  to  find  the  intima  in  arteries 
obtained  post  mortem  to  consist  of  a  single  layer  of  endothelium. 
It  is  much  more  apt  to  be  formed  of  a  cellular  tissue  of  quite  consider- 
able thickness,  and  to  be  irregularly  thick  at  different  parts  of  the 
circle  formed  by  the  vessel.  From  what  is  known  of  embryology,  it  is 
almost  certain  that  this  condition  of  the  intima  does  not  exist  during 
the  earliest  periods  of  development.  How  soon  it  comes  on  and 
whether  it  is  only  a  post-natal  condition  are  important  questions  ;  but 
a  much  more  important  one  is  this — to  what  extent  must  the  intima 
become  thick  or  irregularly  thick  before  the  condition  is  to  be  looked 
upon  as  a  disease  injurious  to  the  well-being  of  the  individual  and  be 
named  endarteritis  or,  if  it  be  of  a  vein,  endophlebitis  ?  Thickening  of 
the  intima  of  the  arteries  is  in  my  opinion  more  common  in  the  heart 
and  in  the  kidneys  than  in  any  of  the  other  organs. 

In  conclusion,  it  may  be  said,  without  much  fear  that  the  statement 
will  be  thought  to  be  exaggerated,  that  the  study  of  the  blood-vessels 
of  the  heart  has  been  a  very  fruitful  one,  more  so  perhaps  than  that 
of  any  other  part  of  the  body. 


CHAPTER    IX 

THE   BLOOD-VESSELS   OF   THE    LUNGS 

IT  would  probably  be  asserted  by  most  anatomists  and  pathologists 
that  the  ramifications  of  the  blood-vessels  of  the  lungs  are  known  to 
their  most  minute  details,  and  that  very  little  remains  to  be  learned  of 
the  pulmonary  circulation.  Such  an  assertion  would  be  entirely 
correct  as  far  as  concerns  the  larger  blood-vessels,  and  most  of  the 
anatomy  of  the  lung  is  unquestionably  well  known.  I  feel  some  doubt, 
however,  in  regard  to  the  completeness  of  our  knowledge  of  the 
minute  structure  of  the  lungs  and  of  their  blood-vessels.  The  large 
blood-vessels,  the  air-tubes,  the  connective  tissue,  and  the  spongy  lung 
tissue  are  bound  together  in  such  a  way  as  to  form  a  very  complicated 
whole.  The  lung  structure  is  a  more  complicated  one  than  that  of 
the  heart,  for  example,  which  is  composed  simply  of  connective  tissue, 
muscle  fibres,  and  blood-vessels.  The  larger  blood-vessels  of  the  heart 
are  arranged  according  to  a  very  simple  plan  upon  the  surface  and  in 
the  substance,  and  the  capillaries  wind  among  and  through  the  fibres. 
The  microscopical  details  of  the  appearances  of  the  larger  blood-vessels 
of  the  lungs  have  not  been  worked  out  and  recorded,  as  it  is  to  be 
hoped  they  some  day  will  be.  It  has  been  impossible  for  me  to  obtain 
a  series  of  normal  human  lung  blood-vessels  of  which  I  could  have 
drawings  made.  My  discussion  will  have  to  be  confined,  therefore, 
almost  entirely  to  the  elucidation  of  the  subject  of  disease  of  the  blood- 
vessels of  the  lungs.  It  is  impossible,  however,  to  study  disease  for 
any  length  of  time  without  learning  much  of  the  normal  conditions  of 
the  various  tissues  and  organs  that  fall  under  observation.  It  may  be 
hoped,  therefore,  in  the  course  of  my  study  of  human  lung  blood- 
vessels, even  if  most  of  them  are  certainly  diseased,  and  the  normal 
condition  of  others  is  doubtful,  that  something  will  be  acquired  to  add 
to  the  sum  of  knowledge  of  anatomy. 

Fig.  76  is  an  illustration  of  a  bronchiole  surrounded  by  lung-tissue 

of  a    negro  woman    twenty-three    years    old   who  died  of   phthisis. 

When  the  autopsy  was  made,  the  pulmonary  artery  was  injected  with 

a  solution  of  Berlin  blue,   and  afterwards  the  tissue  was  stained  in 

90 


FIG.  76. — BRONCHIOLE  OF  INJECTED  LUNG.     (X  115.) 

From  a  negro  woman  twenty-three  years  old  who  died  of  phthisis.  The  tissue  is  stained 
red  and  the  injected  blood-vessels  are  blue.  There  is  a  fringe  of  capillaries  that  forms  the 
greater  part  of  the  lining  of  the  bronchiole,  and  outside  of  this  are  the  submucous  and  the 
muscular  tissues.  There  is  no  sign  of  the  layer  of  columnar  epithelium  which  ordinarily  is 
one  of  the  most  conspicuous  features  of  the  bronchi  and  bronchioles  in  microscopical,  prepa- 
rations. 


FIG.   76. 


2, 

/to     m.nrx 


THE  BLOOD-VESSELS  OF  THE  LUNGS  91 

bulk  with  borax-carmine  and  embedded  in  paraffin.  The  blue  shows 
blood-vessels  filled  by  the  injection,  and  the  red  represents  lung  tissue 
and  the  bronchiole.  A  most  curious  development  of  capillaries  is 
shown.  In  the  natural  condition  the  nutrient  blood-vessels  of  the 
bronchioles  are  distributed  in  the  outer  layers  like  the  vasa  vasorum 
of  the  arteries  and  veins,  but  they  do  not  penetrate  very  deeply  into 
the  substance  of  the  bronchioles.  The  drawing  shows  that  the  capil- 
laries pass  entirely  through  the  wall  and  are  distributed,  as  seen  in  the 
section,  in  the  form  of  a  fringe  upon  the  inner  surface  of  the  air  tube. 
The  folded  and  twisted  appearance  of  the  capillaries  forming  the 
lining  of  the  bronchiole  is  probably  due,  principally  if  not  entirely,  to 
shrinkage  of  the  tissue,  just  as  the  folding  of  the  plicated  membrane 
of  blood-vessels  is  caused.  This  is  an  effect  produced  by  the  prepa- 
ration of  tissues  for  microscopical  examination,  which  has  already 
been  described  (page  9).  In  this  bronchiole  there  are  none  of  the 
columnar  epithelial  cells  which  in  the  natural  condition  form  the  lining 
of  the  minute  air-tubes,  nor  are  there  any  cuboidal  cells  such  as  are 
usually  described  as  lying  next  to  the  layer  of  columnar  cells.  The 
whole  character  of  the  mucous  lining  of  the  tube  is  altered  by  the 
disease.  Inside  the  layer  of  muscle  the  tissue  is  composed  of  round 
cells  and  capillaries;  it  is  a  granulation  tissue  and  it  is  probably  a  good 
deal  thicker  than  the  natural  mucous  layer  was.  I  do  not  know  of 
any  description  or  picture  of  this  condition,  although,  of  course,  the 
increased  vascularity  of  the  mucous  layer  of  inflamed  bronchial  tubes 
is  well  known.  It  is  easy  to  understand  why  the  expectoration  so 
often  becomes  blood-stained,  and  even  why  quite  copious  hemorrhages 
take  place  in  cases  of  bronchitis,  and  of  pneumonia,  and  of  phthisis, 
in  all  of  which  the  bronchioles  are  inflamed,  if  it  is  a  common  effect  of 
such  inflammation  to  cause  the  development  of  capillaries  to  form 
the  lining  of  the  air-tubes.  Every  one  knows  how  apt  the  nose  is  to 
bleed  at  certain  stages  of  attacks  of  coryza,  and  this  is  due  to  the 
increased  vascularity  of  the  mucous  lining.  The  changes  of  the 
mucosa  of  the  nose  are  probably  precisely  similar  to  those  shown  by 
the  drawing,  and  it  is  likely  that  the  various  stages  of  this  process 
are  similar  to  those  that  take  place  in  the  intestine  in  typhoid  fever. 
At  first  probably  the  inflammation  causes  swelling  and  thickening  of 
the  lining  of  the  bronchial  tubes,  then  the  mucous  membrane,  includ- 
ing the  cuboidal  cells  and  ciliated  columnar  epithelium,  is  shed.  Later 


9 2  HUMAN  BLOOD-VESSELS 

the  granulation  tissue,  with  its  abundant  supply  of  capillaries,  is  pro- 
duced as  a  part  of  nature's  attempt  at  regeneration  ;  this  layer  may  be 
of  even  greater  thickness  than  the  natural  mucous  membrane,  as  it 
appears  to  be  in  the  bronchiole  shown  by  the  drawing.  The  condi- 
tions demonstrated  by  this  injected  specimen  are  very  interesting  and 
suggestive. 

Fig.  77  shows  lung-tissue  of  a  man  seventy  years  old  who  died  of 
chronic  myelitis.  There  is  a  central  space  which  appears  to  be  empty 
except  for  a  few  blood-corpuscles  scattered  in  it.  Around  this  is  a 
ring  of  closely  appressed  blood-corpuscles,  outside  of  which  is  lung- 
tissue,  all  of  which  is  infiltrated  with  blood.  The  lung-tissue  is  almost 
indistinguishable,  for  it  looks  like  a  mass  of  blood-corpuscles  with  lines 
and  strings  in  it  and  some  large  cells  and  pigment  granules  scattered 
through.  By  itself,  and  without  the  knowledge  that  the  tissue  is  lung, 
it  is  unlikely  that  it  could  be  recognized.  The  escape  of  the  blood 
from  the  capillaries  of  the  lungs  into  the  air-sacs  is  the  cause  of  death 
in  the  great  majority  of  people  who  die  from  natural  causes.  Laennec 
said  that  the  brain,  the  heart,  and  the  lungs  are  the  three-legged 
stool  (trepiecf)  of  life,  and  that  death  occurs  much  more  frequently 
from  cessation  of  the  function  of  the  lungs  than  from  stoppage  of 
the  action  of  the  brain  or  of  the  heart.  The  illustration,  therefore, 
represents  an  exceedingly  common  condition,  and  one  of  great  im- 
portance. When  it  is  learned  what  happens  toward  the  end  of  life 
to  cause  the  capillaries  to  fail  any  longer  to  perform  their  work  of 
containing  and  conveying  the  blood  and  it  transudes  into  the  air- 
spaces until  life  can  no  longer  be  maintained,  a  great  advance  in 
physiology  and  in  pathology  will  result.  The  lung  represented  by 
Fig.  77  is  that  of  an  old  man  who  had  extensive  fibroid  disease  of 
several  of  his  organs,  and  it  is  probable  that  the  space  in  the  lung 
which  is  partly  filled  by  blood  is  an  emphysematous  cavity.  The 
exact  effects  of  emphysema  upon  the  blood-vessels  are  not  yet  com- 
pletely known,  but  it  is  beyond  question  that  it  reduces  the  vascu- 
larity  of  any  portion  of  lung  that  has  become  emphysematous.  The 
number  of  the  air-sacs  is  reduced  by  the  breaking  of  many  of  them 
into  one,  and  this  must  reduce  the  total  area  of  their  wall  surface 
which  is  the  carrier  of  the  capillaries  that  oxygenate  the  blood.  In 
addition  to  this,  it  is  almost  certain  that  the  walls  of  the  enlarged  em- 
physematous vesicles  are  less  richly  supplied  with  capillaries  than  the 


FIG.  77. — INFILTRATION  OF  THE  LUNG  WITH  BLOOD.      (X  100. ) 

From  a  man  of  seventy  years  who  died  of  chronic  myelitis.  The  lung-tissue  is  filled  with 
infiltrated  blood-corpuscles,  a  is  the  edge  of  an  emphysematous  cavity.  The  portion  of  this 
cavity  between  a  and  b  is  filled  with  blood-corpuscles  which  were  pressed  into  it  from  the 
surrounding  lung-tissue.  In  the  centre  the  space  is  nearly  empty, — it  contains  a  few  blood- 
corpuscles.  The  lung-tissue  is  distinguishable  merely  as  lines  and  strings  running  through 
the  mass  of  exuded  blood-corpuscles.  To  the  left  there  is  a  good  deal  of  pigment.  Such 
blood-exudation  into  the  lung  generally  occurs  during  the  last  few  hours  of  life.  Only  those 
who  die  suddenly  escape  it. 


FIG.  77. 


THE  BLOOD-VESSELS  OF  THE  LUNGS  93 

natural  ones.  It  is  highly  probable,  although  at  present  impossible  to 
prove,  that  emphysema  is  in  part  due  to  the  fact  that  the  increase  of 
fibrous  tissue,  which  is  an  essential  part  of  the  process,  thickens  and 
hardens  the  walls  of  the  air-sacs,  reduces  their  vascularity,  and  lowers 
their  vitality,  so  that  many  air-vesicles  become  one  by  the  breaking 
of  their  intervening  walls.  It  has  long  seemed  to  me  that  under  cer- 
tain circumstances  emphysema,  which  is  a  condition  of  disease,  may 
be  conservative  of  life.  The  number  of  the  air-vescicles  is  beyond 
question  reduced  and  their  size  is  increased.  They  become  so  large 
that  after  death  they  may  often  be  seen  with  the  unaided  eye  stand- 
ing out  upon  the  surface  of  the  lung  as  membranous  blebs.  If  it  is  a 
fact  that  the  walls  of  emphysematous  air-sacs  are  less  richly  supplied 
with  capillaries,  it  almost  necessarily  follows  that  the  diseased  lung 
made  up  of  larger  air-spaces  which  are  less  vascular  will  not  be  so 
prone  to  fill  with  blood.  The  old  man  of  seventy  whose  lung  is  rep- 
resented by  Fig.  77  died  of  chronic  myelitis,  but  it  was  discovered 
after  his  death  that  he  had  extensive  fibrosis  of  the  kidneys  and  of 
other  organs.  His  death,  which  came  after  a  very  prolonged  illness, 
was  caused  by  filling  up  of  the  lungs  ;  it  was  gradual  in  its  approach, 
unlike  those  cases  where  death  occurs  suddenly  by  cessation  of  func- 
tion of  the  brain  or  of  the  heart.  It  seems  to  me  almost  certain  that 
if  the  lung  had  been  less  fibroid  and  less  emphysematous — the  air- 
cavities  therefore  smaller  and  the  supply  of  blood  larger — the  trans- 
udation  of  the  blood  into  the  lung  would  have  occurred  sooner  and 
more  rapidly,  and  death  would  not  have  been  so  long  delayed.  The 
illustration  shows  that  even  after  death  the  cavity  seen  in  the  centre 
of  the  drawing  had  only  partly  filled  with  blood,  while  the  surrounding 
air-vescicles  are  entirely  filled  by  the  corpuscles  which  had  escaped 
from  the  capillaries. 

Figs.  78,  79,  and  80,  and  Figs.  81,  82,  and  83  together  constitute 
a  group  of  illustrations  which  show  a  curious  result  of  disease  upon 
the  lungs  and  upon  their  blood-vessels.  Figs.  78,  79,  and  80  are 
drawn  with  low  amplification,  and  Figs.  81,  82,  and  83  give  repre- 
sentations of  portions  of  the  same  lungs  more  highly  magnified,— 
showing  something  of  the  details  of  structure.  Fig.  78  depicts  lung  of  a 
woman  twenty-three  years  old  who  died  of  typhoid  fever.  The  lung 
appears  nearly  solid  and  the  tissue  is  ill  defined.  Careful  study  of 
the  section  with  higher  amplification  makes  it  certain  that  there  is  a 


94  HUMAN  BLOOD-VESSELS 

good  deal  of  partially  disintegrated  blood.  Fig.  79  shows  lung  of 
a  negro  woman  twenty-eight  years  old  who  died  of  catarrhal  pneumo- 
nia. It  is  by  no  means  solid,  but  on  the  other  hand  the  lung  is  of  a 
much  less  open  and  spongy  texture  than  is  natural.  There  are  open 
air-sacs  alternated  with  patches  that  are  more  or  less  solid.  When 
examined  with  higher  amplification  this  lung  shows  no  evidence  of 
disintegration  ;  the  tissue  is  clearly  definable,  and  the  walls  of  the  air- 
sacs,  the  capillaries,  and  the  blood-corpuscles  within  them,  are  in 
many  places  easy  to  distinguish,  although  in  other  and  more  solid 
portions  the  appearance  is  much  like  that  of  Fig.  78.  Fig.  80  shows 
lung  of  a  negro  man  forty-nine  years  old  who  died  of  Bright's  disease. 
Far  from  presenting  an  appearance  of  solidity,  the  lung  is  of  more 
open  texture  than  is  natural.  Examination  with  greater  amplification 
shows  the  tissue  to  be  sharply  defined.  In  the  walls  of  the  air-sacs 
the  turns  of  the  capillaries  are  easy  to  see,  and  so  are  the  blood- 
corpuscles  that  in  many  places  lie  within  them.  These  three  drawings, 
when  considered  together,  illustrate  curious  effects  of  acute  and 
chronic  diseases  and  the  effects  of  disease  at  different  ages  upon  the 
lungs.  Fig.  78  is  from  a  young  adult  who  died  of  typhoid  fever, 
which  is  a  purely  acute  disease,  and  the  tissue  appears  nearly  solid. 
Fig.  79  is  also  from  a  young  adult,  but  death  was  owing  to  catarrhal 
pneumonia — a  disease  only  semi-acute  in  character — and  the  tissue, 
although  denser  than  normal,  is  by  no  means  solid.  Fig.  80  is  from  a 
man  past  middle  life  who  died  of  a  chronic  disease,  and  the  tissue,  far 
from  being  solid,  is  even  more  spongy  and  of  open-meshed  character 
than  is  natural.  These  microscopical  appearances  correspond  exactly 
with  the  gross  appearances  of  the  lungs  often  found  at  post-mortem 
examination.  In  typhoid  fever  the  exudation  is  frequently  so  great 
that  the  natural  sponginess  of  the  lung  is  destroyed,  and  it  is  in  ap- 
pearance nearly  solid.  In  catarrhal  pneumonia  the  sponginess  is  re- 
duced, but  the  tissue  is  likely  to  look  less  solid ;  while  in  Bright's  disease 
(if  it  was  of  chronic  character)  the  lung  is  often  emphysematous  and 
is  even  more  spongy  than  normal  lung  is.  In  purely  acute  disease, 
the  lung  is  apt  to  become  and  easily  can  become  solid.  In  less  acute 
or  semi-chronic  disease,  this  tendency  is  much  less  ;  while  in  chronic 
disease,  when  there  has  been  antecedent  or  accompanying  degenera- 
tion, the  lung  remains  open  and  spongy,  the  fibrosis  seeming,  as  has 
already  been  said,  to  have  an  effect  which  may  be  conservative  of 


FIG.  78. — LUNG.     (X  20. ) 

From  a  woman  twenty-three  years  old  who  died  of  typhoid  fever.  The  lung  appears 
nearly  solid,  for  most  of  the  air-spaces  are  filled,  a,  the  region  shown  more  highly  mag- 
nified by  Fig.  8l.  Compare  with  Figs.  79  and  80. 

FIG.  79. — LUNG.      (X  20.) 

From  a  negro  woman  twenty- eight  years  old  who  died  of  catarrhal  pneumonia.  The 
lung  is  much  more  nearly  solid  than  natural,  but  many  of  the  air-sacs  are  visible  as  empty 
spaces,  b,  the  region  shown  more  highly  magnified  by  Fig.  82. 


FIG.  78. 


FIG.  79. 


FIG.  80. — LUNG.     (X  20.) 

From  a  negro  man  forty-nine  years  old  who  died  of  Bright's  disease.  The  tissue  is  of 
more  open-meshed  appearance  than  is  natural,  for  there  is  emphysema  of  the  lung,  c,  the 
region  shown  more  highly  magnified  by  Fig.  83. 


FIG.  80. 


THE  BLOOD-VESSELS  OF  THE  LUNGS  95 

life.  This  is  because  it  is  more  difficult  for  transudation  of  blood  into 
the  air-sacs  to  occur,  and  therefore  less  easy  for  one  of  the  legs  of 
what  Laennec  has  called  the  three-legged  stool  of  life  (the  brain,  the 
heart,  and  the  lungs)  to  become  unable  to  sustain  its  portion  of  the 
burden.  The  questions  whether  the  blood-vessels  undergo  any  struc- 
tural alteration  in  such  conditions  of  disease  as  those  shown  by  Figs. 
78,  79,  and  80,  and,  if  there  is  any  alteration  of  structure,  whether  it 
is  antecedent  or  subsequent,  or  if  it  is  causative  or  resultant,  are 
very  important  ones.  There  is  no  doubt  that  in  cases  of  chronic 
disease  of  almost  all  kinds  the  larger  blood-vessels  are  more  or  less 
abnormal  in  the  majority  of  instances,  and  that  they  change  with 
the  progress  of  life,  being  found  to  be  further  and  further  away  from 
the  standards  of  the  normal  as  men  grow  older.  It  is,  however, 
much  more  difficult  to  be  certain  whether  the  changes  of  the  larger 
blood-vessels — which  are  inevitable  to  advancing  age  and  common  in 
chronic  disease  at  all  periods  of  life,  and  are  often  found  even  in  the 
very  young — are  causes  of  disease  or  are  its  consequences.  This 
subject  has  been  discussed  in  various  parts  of  my  book  on  the  "  Origin 
of  Disease"  and,  in  fact,  it  is  the  theme  upon  which  much  of  it  is 
built ;  I  will  not  therefore  pursue  its  discussion  any  further  now.  The 
condition  of  the  capillaries,  and  the  questions  whether  they  become 
diseased  and  if  their  physical  state  can  have  any  influence  in  the  pro- 
duction of  disease,  are  difficult  ones,  and  the  subject  is  one  in  regard 
to  which  much  remains  to  be  learned.  If  I  am  right  in  my  previously 
expressed  belief  (page  17)  that  the  capillaries  are  evanescent  and 
come  and  go  in  the  tissues  as  they  are  needed,  it  is  unlikely  that  the 
subject  of  disease  of  capillaries  ever  will  be  formulated  in  the  same 
way  as  that  of  disease  of  the  larger  blood-vessels  is  likely  to  be. 

Figs.  8 1,  82,  and  83  represent  more  highly  magnified  the  regions  a, 
b,  and  c  of  Figs.  78,  79,  and  80.  The  greatest  care  was  exercised  by 
the  artist  to  approach  as  nearly  as  possible  to  a  reproduction  of  the 
appearances  of  the  tissues  themselves,  and  I  am  convinced,  by  what 
I  have  seen  in  the  course  of  the  examination  of  a  great  many  capil- 
laries and  by  what  is  shown  by  these  drawings,  that  in  disease  there 
is  often  a  real  physical  alteration  of  the  capillaries  themselves.  A 
prolonged  study  of  the  capillaries  has  brought  me  to  this  con- 
viction, but  it  has  been  attained  by  seeing  in  one  section  a 
single  capillary,  and  in  another  a  minute  bit  of  tissue,  and  in  a  third 


96  HUMAN  BLOOD-VESSELS 

something  else  that  tended  to  the  same  end.  Much  of  the  evidence, 
therefore,  upon  which  my  conviction  is  founded  is  of  such  a  nature 
that  it  can  only  be  told  and  nothing  brought  forward  to  demonstrate 
it  by  pictures.  It  has  been  exceedingly  difficult  to  obtain  tissues  that 
show  enough  of  the  changes  in  the  minute  areas  that  can  be  included 
in  single  fields  examined  under  high  power  with  the  microscope, — and 
it  must  be  remembered  that  capillaries  cannot  be  seen  at  all  unless 
they  are  quite  highly  magnified.  In  drawing  any  conclusions  in  re- 
gard to  disease  of  the  capillaries  from  such  preparations  as  those 
represented  by  the  illustrations,  it  should  always  be  kept  in  mind  that 
it  is  almost  certain  that  the  capillaries  in  the  living  human  tissues  are 
branching  tubes  which  run  a  reasonably  direct  course,  and  that  they 
probably  closely  resemble  those  which  may  so  easily  be  seen  in  the 
tail  of  the  living  tadpole.  The  convolutions  and  tortuosities  of  the 
capillaries  represented  by  Figs.  82  and  83,  which  make  them  look 
like  masses  of  earthworms  as  they  intertwine  themselves  when  many 
of  them  are  put  together,  are  produced  to  a  great  extent  by  the  shrink- 
age of  the  tissue  in  the  course  of  its  preparation  in  various  reagents 
before  it  is  cut  in  sections  for  examination  with  the  microscope.  The 
resulting  appearance  is  similar  to  the  folding  of  the  plicated  membrane 
of  the  arterioles,  which  in  living  tissues  is  straight,  as  already  described 
(page  1 2).  Fig.  8 1  shows  a  portion  of  the  walls  of  air-sacs  and  a  bit 
of  exudative  substance  which  lay  loosely  in  an  air-vesicle.  The 
tissue  is  ill-defined  in  appearance :  there  are  cells  of  the  lung,  and 
the  remains  of  blood-corpuscles  which  are  partly  disintegrated  can 
be  seen  as  imperfectly  formed  circles,  but  no  capillaries  can  be  dis- 
tinguished. When  considerable  portions  of  sections  of  this  lung  are 
examined,  it  is  easy  to  determine  that  there  was  extensive  exuda- 
tion of  blood,  and  Fig.  78  shows  that  the  lung  was  nearly  solid.  The 
patient,  who  was  young,  died  of  an  acute  attack  of  typhoid  fever  and 
probably  had  no  antecedent  chronic  or  latent  disease  :  the  capillaries 
had  not  undergone  any  physical  alteration,  and  the  cause  of  the 
transudation  of  blood  into  the  lung-tissue  and  into  the  air-sacs  under 
such  circumstances  is  at  present  beyond  the  reach  of  explanation. 
Fig.  82  is  also  a  portion  of  the  walls  of  air- sacs,  and  there  are  a  few 
scattered  exudate  cells.  The  lung-tissue  contains  many  cells  and  the 
capillaries,  which  are  tortuous,  are  easily  distinguished.  In  places  the 
circular  blood-corpuscles  can  be  seen,  but  more  commonly  the  blood 


THE  BLOOD-VESSELS  OF  THE  LUNGS  97 

has  lost  its  distinctive  appearance.  This  lung,  which  is  also  repre- 
sented by  Fig.  79,  was  in  places  nearly  solid  and  in  others  quite  open 
meshed.  The  patient,  although  a  young  adult,  died  of  a  subacute 
disease.  It  is  fair  to  conclude  that  the  capillaries  are  normal,  or  if  at 
all  abnormal  that  they  are  only  a  little  thickened.  Fig.  83  is  also  a 
portion  of  the  lung  showing  the  walls  of  air-sacs.  The  appearance  of 
this  portion  of  the  lung  presents  a  striking  contrast  to  that  of  the  two 
others  just  described.  The  walls  of  the  air-sacs  are  from  two  to  four 
times  thicker  and  the  tissue  is  of  a  much  denser  and  coarser  texture, 
which  gives  to  it  an  appearance  of  heaviness.  There  are  a  great  many 
capillaries  which  are  very  tortuous  and  there  is  not  the  slightest 
difficulty  in  seeing  them.  Many  of  the  capillaries  contain  blood- 
corpuscles  which  are  not  disintegrated,  but  preserve  their  distinctive 
appearance.  It  is  to  be  remembered  that  this  lung,  which  is  rep- 
resented less  highly  magnified  by  Fig.  80,  was  even  more  open 
meshed  in  appearance  than  normal  lung.  The  patient,  who  was  past 
middle  life,  died  of  a  chronic  disease,  and  probably  there  was 
slowly  progressive  and  increasing  fibroid  disease  of  his  tissues  and  or- 
gans. The  contrast  presented  by  the  three  drawings,  Figs.  78,  79,  and 
80,  and  Figs.  81,  82,  and  83,  is  very  striking  and  instructive.  Fig.  78, 
a  low-power  picture,  is  the  most  solid  of  the  three,  while  Fig  8 1,  which 
is  the  same  lung  under  greater  amplification,  appears  least  solid  of  the 
second  three  drawings.  Fig.  79  is  less  solid,  occupying  in  this  respect 
a  middle  place,  while  Fig.  82  is  of  less  light  texture,  more  solid  per- 
haps it  may  be  said  than  Fig.  81,  of  the  second  three.  Fig.  80  is  the 
least  solid  of  the  three,  or  more  correctly  it  is  not  solid  at  all,  but  is 
unnaturally  open  meshed  and  of  a  light  texture.  Fig.  83,  on  the  other 
hand,  is  the  most  solid  looking  of  the  three  drawings  made  with  higher 
amplification.  Thus  it  is  seen  that  the  one  of  the  three  lungs  which 
when  examined  but  little  magnified  is  the  most  solid,  appears  on  the 
other  hand  of  the  lightest  texture  when  highly  magnified,  while  that 
which  when  examined  with  low  amplification  is  seen  to  be  open  meshed 
appears  to  be  the  most  solid  when  it  is  highly  magnified.  The  mid- 
dle position  of  solidity  is  naturally  held  by  the  second  of  the  drawings 
of  both  of  the  groups.  Figs.  81,  82  and  83  have  confirmed  me  in  the 
opinion  that  the  capillaries  undergo  actual  physical  alteration  in  dis- 
ease. This  opinion,  as  has  already  been  said,  I  have  long  held  on  ac- 
count of  what  I  have  seen  in  the  course  of  the  examination  of  many 
7 


98  HUMAN  BLOOD-VESSELS 

sections  of  various  tissues  in  which  capillaries  could  be  distinguished  ; 
but  it  seems  to  me  that  Fig.  83  demonstrates  disease  of  the  capillaries. 
The  physical  change  consists  in  an  increase  of  the  thickness  of  their 
walls.  A  great  effort  was  made  by  the  artist  to  represent  correctly  the 
appearance  of  the  tissues,  and  it  is  easy  to  recognize  that  the  walls  of 
the  capillaries  of  Fig.  83  are  of  much  heavier  texture  than  those  of 
Fig.  82,  which  are  natural,  or,  if  they  are  diseased  at  all,  it  is  but  little. 

It  is  quite  impossible  at  present  to  know  the  significance  of  such 
disease  of  the  capillaries,  but  the  mere  demonstration  of  its  existence 
may  be  a  matter  of  considerable  importance.  If  my  contention  that 
the  capillaries  are  evanescent,  and  come  and  go  in  the  tissues  as  they 
are  needed,  is  correct,  it  is  probable  that  in  lung-tissue  like  that  rep- 
resented by  Fig.  83  they  develop  less  readily  because  the  tissue  is 
fibrous  and  hard,  and  that  the  same  fibrous  density  which  diminishes 
their  facility  of  development  renders  them  less  easily  extinguishable. 
The  density  of  the  walls  of  the  air-sacs  probably  makes  more  difficult 
the  transudation  of  blood,  which  in  the  great  majority  of  cases  is  the 
direct  cause  of  death.  This  lends  confirmation  to  the  view  that 
emphysema  is  sometimes  conservative  of  life. 

My  illustrations  (Figs.  81,  82,  and  83)  are  etchings  which  were  drawn 
with  the  camera  lucida  on  steel  directly  from  sections,  and  they  are  as 
accurate  as  pictures  can  be,  for  the  method  is  the  best  of  which  I 
know,  and  the  artist  is  very  skilful  and  exercised  the  greatest  care  in 
making  them.  It  would  be  difficult  to  exaggerate  the  importance  of 
the  lessons  taught  by  these  three  drawings.  There  are  several  of  these 
lessons.  First,  the  different  tissues  are  of  different  degrees  of  density. 
Second,  the  tissue  disintegrates  before  death  in  persons  who  die 
quickly  of  acute  diseases,  while  the  definition  of  all  the  different 
elements  of  the  tissue  is  clear  and  sharp  in  those  who  die  slowly  and 
of  chronic  disease,  and  such  tissues  are  satisfactory  ones  to  study  with 
the  microscope.  Last,  but  most  important  of  all,  is  the  increased 
thickness  of  the  walls  of  the  capillaries  and  the  general  increase  of 
the  fibrous  tissue  in  the  walls  of  the  air-sacs  of  the  lungs,  as  demon- 
strated by  Fig.  83.  The  effects  of  emphysema  and  fibrosis,  which 
are  inevitable  accompaniments  of  age,  and  often  occur  in  the  young 
who  are  prematurely  old,  is  a  subject  of  the  highest  importance, 
and  the  question  how  much  influence  the  growth  of  fibrous  tissue 
has  in  the  production  of  the  physical  appearances  commonly  called 


FIG.  8 1.— LUNG.     (X  260. ) 

The  region  a  from  Fig.  78  more  highly  magnified.  There  is  a  portion  of  the  walls  of 
air-sacs  and  a  little  exudative  material  below.  The  capillaries  of  the  lung  cannot  be  seen. 

FIG.  82. — LUNG.     (X  260.) 

The  region  b  from  Fig.  79  more  highly  magnified.  The  walls  of  air-sacs  and  scattered 
exudative  material.  The  capillaries  can  be  distinctly  seen,  and  blood-corpuscles  in  some  of 
them. 

FIG.  83. — FIBROID  LUNG.     (X  260.) 

The  region  c  from  Fig.  80  more  highly  magnified.  The  walls  of  the  air-sacs  are  thick 
and  the  capillaries  are  easily  seen.  Many  of  them  are  filled  with  blood-corpuscles  and  the 
capillary  walls  are  thicker  than  is  normal. 


-•' 


Fig.  8  3 


THE  BLOOD-VESSELS  OF  THE  LUNGS  99 

those  of  age  in  human  beings,  and  how  much  all  of  this  may  be 
counterfeited  in  younger  persons  by  disease  or  by  the  effects  of  bad 
habits  and  unhygienic  living,  is  of  fascinating  interest.  My  book 
upon  the  "Origin  of  Disease"  is,  to  a  great  extent,  made  up  by  the 
discussion  of  these  and  allied  questions,  and  it  is  therefore  unnecessary 
now  to  enlarge  upon  them  further  than  to  say  once  more  that  it  is 
important  that  the  changes  induced  by  fibrosis  should  be  studied  from 
every  possible  stand-point,  so  that  the  most  minute  changes  that  can 
be  recognized  by  the  use  of  the  microscope  may  become  well  known. 
Thickening  of  the  walls  of  the  capillaries,  such  as  that  shown  by  Fig. 
83,  is  probably  one  of  the  early  changes,  and  it  is  very  much  to  be 
desired  that  in  time  it  may  be  learned  whether  it  has  any  causative 
influence  in  producing  fibrosis,  or  if  it  is  solely  a  consequence.  It  is 
certainly  true  that  much  disease — probably  most  of  the  chronic  disease 
— is  of  intrinsic  origin,  and  has  nothing  to  do  with  extrinsic  poisons 
either  of  a  material  or  of  other  nature.  If  such  be  the  case,  it  is  most 
likely  that  the  blood-vessel  system — which  goes  to  all  parts  of  the 
body  and  connects  every  part  with  every  other  part— is  early  affected 
in  the  course  of  chronic  disease,  and  that  the  blood-vessels  have  a 
causative  relation  to  the  spread  of  the  disease  from  their  own  walls 
and  contained  fluid  to  other  tissues  and  organs.  I  do  not  wish  to 
exaggerate  the  importance  of  the  intrinsic  origin  of  disease  at  the 
expense  of  truth,  but  at  the  present  time  there  is  so  much  exagger- 
ation and  so  much  misstatement  in  regard  to  the  causation  of  disease 
by  micro-organisms,  that  it  becomes  almost  necessary  to  overstate 
the  opposite  position  in  order  to  offset  the  ill  that  is  done  by  erroneous 
views  now  prevailing. 

Figs.  84  and  85  show  fibroid  disease  of  blood-vessels  of  the  lung. 
They  are  both  from  a  negro  infant  one  year  old  who  died  of  chronic 
catarrhal  pneumonia.  He  had  whooping-cough  when  six  months 
old,  which  ran  into  catarrhal  pneumonia,  and  it  soon  became  chronic, 
and  from  this  disease  he  never  recovered.  The  cough  did  not  at  any 
time  cease,  although  there  were  periods  of  improvement  when  it  was 
hoped  he  would  get  well.  At  times  it  was  thought  the  disease  was 
tuberculosis.  As  this  infant  was  ill  for  six  months  and  was  only  one 
year  old  when  he  died,  he  was  continuously  diseased  during  half  of 
his  life,  which  certainly  justifies  the  statement  that  the  attack  was 
chronic.  At  the  post-mortem,  the  examination  with  the  unaided  eye 


TOO  HUMAN  BLOOD-VESSELS 

failed  to  bring  to  light  any  evidence  of  disease  of  the  lungs,  the  tissue 
of  which  appeared  light  and  spongy.  After  portions  of  it  had  been 
properly  prepared,  a  number  of  sections  were  taken  from  various 
regions  and  were  cut.  These  sections  show  at  once,  and  even 
before  they  are  studied  with  the  microscope,  that  the  lung  is  greatly 
diseased.  Most  of  the  tissue  is  of  open-meshed  character  and  is 
quite  normal,  but  scattered  through  this  normal  tissue  are  minute 
spots  which  are  much  denser.  Examination  with  the  microscope 
shows,  even  when  low  amplification  is  used,  that  the  denser  areas 
almost  all  include  within  them  bronchioles  and  blood-vessels.  Careful 
study  shows  that  evidence  of  the  existence  of  tuberculosis  is  entirely 
wanting.  The  case  therefore  is  a  typical  one  of  broncho-pneumonia. 
It  is  believed  by  many  that  that  disease  has  its  origin  in  bronchitis 
and  that  the  inflammation  spreads  from  the  bronchi  to  the  surround- 
ing tissue,  thus  producing  peribronchitis,  which  must  at  the  same  time 
cause  perivascular  disease,  because  the  blood-vessels  and  bronchi 
generally  lie  together,  and  it  would  therefore  be  impossible  for  the 
diseased  tissue  to  surround  the  bronchi  without  including  also  many 
blood-vessels. 

Fig.  84  is  almost  certainly  an  arteriole  and  not  a  vein,  for  veins  do 
not  have  such  a  distinct  plicated  membrane.  The  intima,  the  plicated 
membrane,  and  the  muscularis  might  almost  be  selected  as  types  of 
what  it  is  most  common  to  find  post  mortem  in  human  beings  dead  of 
disease.  They  are  not  typically  normal,  but,  on  the  other  hand,  there 
is  no  evidence  of  very  extensive  disease,  or  of  any  disease  that  need 
have  prevented  the  vessel  performing  its  function.  The  intima  is 
moderately  thickened,  for  it  is  a  cellular  ring  of  quite  considerable 
diameter,  instead  of  being  formed  of  a  single  layer  of  endothelial 
plates,  as  the  histologists  teach  is  normal  in  such  minute  arterioles  as 
this.  The  plicated  membrane  is  strikingly  distinct  and  the  muscu- 
laris is  not  of  exactly  even  thickness,  being  a  little  thicker  at  some 
of  its  parts  than  at  others.  Outside  the  muscularis  there  is  a 
ring  of  fibrous  tissue  of  great  thickness.  The  presence  of  a  fibrous 
ring  like  this  around  an  arteriole  raises  again  the  question  which  has 
already  been  discussed  (Fig.  33),  whether  it  should  be  classed  as 
the  thickened  adventitia  of  the  vessel  or  if  it  is  perivascular  con- 
nective tissue.  There  is  nothing  in  the  nature  or  in  the  appear- 
ance of  this  or  of  any  other  fibrous  tissue  which  surrounds  blood- 


FIG.  84. — PERIVASCULAR  FIBROSIS  OF  LUNG.     (X  50.) 

From  a  negro  infant  one  year  old  who  died  of  chronic  catarrhal  pneumonia.  The 
striking  feature  exhibited  by  the  arteriole  is  the  thickening  of  fibrous  tissue  which  surrounds 
the  muscular  coat.  How  much  of  this  should  be  classified  as  adventitia,  and  therefore  as  an 
integral  part  of  the  vessel,  and  how  much  is  perivascular  connective  tissue,  it  is  impossible 
to  determine.  It  is  certain  that  so  much  connective  tissue  around  a  small  arteriole  of  an 
infant  is  not  natural. 

(  V3 

•     V      \U      - 

FJG.  85. — PERIVASCULAR  AND  PERIBRONCHIAL  PNEUMONIA.     (X  20.) 
\>      \l 
From  the  same  patient  as  Fig.  84.     A  blood-vessel  with  two  bronchioles  above  it,  in 

lung-tissue.  The  blood-vessel  is  probably  an  arteriole,  but  of  this  it  is  not  possible  to  be 
certain  because  of  the  changes  caused  by  disease.  The  blood-vessel  and  bronchioles  are 
surrounded  with  dense  tissue.  The  perivascular  and  peribronchial  tissue  is  composed  prin- 
cipally of  round  inflammation  cells  and  contains  many  new  blood-vessels,  some  of  which  can 

be  seen  even  with  the  low  amplification  which  was  used  in  drawing  the  picture. 
\ 


FIG.  84. 


THE  BLOOD-VESSELS  OF  THE  LUNGS  101 

vessels  to  make  it  possible  to  draw  a  distinction  between  adventitia 
and  perivascular  connective  tissue.  This  uncertainty  is  of  course 
entirely  unimportant  as  far  as  concerns  the  possibility  of  understanding 
the  disease,  for  the  question  is  one  purely  of  nomenclature.  The 
great  mass  of  fibrous  tissue  surrounding  this  arteriole  is  surely  morbid, 
and  as  in  this  instance  the  arteriole  stands  by  itself,  there  being  no 
bronchiole  very  near,  it  affords  evidence  which  seems  to  negative  the 
theory  that  broncho-pneumonia  results  only  from  an  extension  of 
inflammation  of  the  bronchi  to  the  surrounding  tissues.  The  appear- 
ance presented  makes  one  think  of  the  classical  essays  of  Gull  and 
Sutton  and  of  their  descriptions  of  what  they  have  named  arterio- 
capillary  fibrosis.  This  disease  they  believed  to  have  its  origin  in 
the  adventitia  of  the  blood-vessels  and  to  be  a  prolific  cause  of 
chronic  disease.  All  questions  of  the  origin  of  disease  are  very  dim- 
cult,  and  as  far  as  regards  real  knowledge  of  final  causes  it  may  truth- 
fully be  said  that  it  has  not  as  yet  been  attained.  Fig.  84  demon- 
strates a  form  of  fibroid  disease  of  the  lung,  and  in  the  special  instance 
the  fibrosis  is  around  an  arteriole  ;  but  whether  the  disease  is  truly  of 
vascular  origin  or  if  it  is  due  to  some  other  cause  is  not  now  known. 
The  growth  of  morbid  fibroid  tissue  around  the  arterioles  is  a  much 
less  common  form  of  disease  than  thickening  of  them  from  within 
owing  to  disease  of  the  intima. 

Fig.  85  is  an  illustration  of  lung- tissue  from  the  same  infant  as 
Fig.  84.  There  are  two  bronchioles  and  a  blood-vessel  which  is 
probably  an  arteriole.  The  three  tubes  are  surrounded  by  dense 
tissue  which  is  composed  principally  of  round  cells,  and  it  contains 
many  new  blood-vessels.  Some  of  these  can  be  seen  even  with  the  low 
power  which  was  used,  and  they  are  shown  by  the  drawing.  Greater 
amplification  is  required  to  bring  out  details  of  structure  and  show 
how  numerous  the  vessels  are.  When  the  section  is  examined  more 
highly  magnified  it  is  seen  that  the  minute  vessels  have  the  character 
that  is  common  to  new  blood-vessels  which  grow  in  inflamed  tissues  ; 
they  are  formed  entirely  of  fibrous  tissue  which  is  of  greater  or  less 
thickness  in  accordance  with  their  size.  It  is  very  unusual  for  vessels 
of  this  character  to  have  three  coats.  The  arteriole  is  filled  with 
blood,  but  like  Fig.  84  its  intima  and  muscularis  are  little  if  at  all  dis- 
eased. The  vessel  is  surrounded  by  thickened  fibrous  tissue.  The 
two  bronchioles,  like  the  arteriole,  are  surrounded  by  rings  of  dense 


io2  HUMAN  BLOOD-VESSELS 

tissue  which  also  contain  many  new  blood-vessels.  These  are  dis- 
tinctly indicated  by  the  drawing,  although,  as  has  been  said,  the  ampli- 
fication used  was  low.  The  lumina  of  the  two  air-tubes  are  partially 
filled  by  some  material  which  is  probably  disintegrated  mucus  that 
would  have  been  discharged  as  expectoration  had  life  been  suffi- 
ciently prolonged.  The  mucous  lining  of  the  bronchi  is  distinctly 
visible,  and  it  may  be  that  it  is  a  little  thickened  or  the  cells  proliferated 
owing  to  the  bronchial  inflammation  which  existed.  The  disease 
exhibited  by  the  drawing  is  an  increase  of  fibrous  tissue  around  the 
bronchi  and  around  the  arteriole,  and  it  is  exactly  similar  to  and  a 
part  of  the  same  disease  as  that  shown  by  Fig.  84.  This  curious 
morbid  fibrosis  occurred  in  an  infant  one  year  old  who  was  ill  with 
chronic  disease  during  half  of  his  brief  life.  Fibrosis  of  this  character 
is  in  many  respects  similar  to  that  which  inevitably  occurs  in  the  aged, 
but  which  in  some  individuals  begins  much  earlier  than  in  others. 
Whether  its  primary  seat  and  its  cause  lie  in  the  blood-vessels  or 
elsewhere  is  a  question  which  remains  for  the  future  to  answer. 

Fig.  86  is  an  illustration  of  a  vein  of  a  man  forty  years  old  who 
died  of  an  attack  that  was  called  typhoid  fever.  The  clinical  history 
and  the  post-mortem  examination,  however,  when  they  are  considered 
together,  make  the  correctness  of  the  diagnosis  somewhat  doubtful ; 
but  whether  it  is  correct  or  incorrect,  it  is  reasonably  certain  that  the 
man  had  suffered  from  a  malady  which  caused  some  chronic  fibrosis 
of  his  organs  prior  to  the  fatal  attack.  The  blood-vessel  shown  by 
Fig.  86  is  called  a  vein  because  its  inner  coat  and  the  muscularis  look 

o 

so  much  more  like  those  of  veins  than  of  arteries.  The  intima  is  not 
well  defined,  and  the  muscular  tissue  is  of  open  texture,  as  it  has  been 
shown  (Fig.  13)  that  the  muscularis  of  veins  is, — a  condition  quite  dif- 
ferent from  that  of  the  muscularis  of  arteries,  which  has  an  appearance 
of  greater  density.  The  striking  feature  of  the  blood-vessel  is  the 
thick  ring  of  fibrous  tissue  by  which  it  is  surrounded.  The  disease  is 
somewhat  similar  to  that  shown  by  Figs.  84  and  85.  This  form  of 
disease  of  blood-vessels  is  much  less  common  than  thickening  of  the 
intima. 

Fig.  87  illustrates  a  portion  of  the  lung  of  a  man  sixty-four  years 
old  who  died  of  rapid  phthisis.  The  drawing  includes  a  portion  of 
the  pleura,  and  there  are  numerous  blood-vessels  of  the  character 
which  it  is  common  to  find  in  tissues  that  were  inflamed  and  in  which 


FIG.  86. — FIBROID  VEIN  OF  LUNG.     (X  50.) 

From  a  man  forty  years  old  who  died  of  typhoid  fever,  e,  epithelium  of  a  bronchiole  ; 
f,  cartilage  ;  b,  the  vein.  The  true  venous  wall  is  thin,  but  it  is  surrounded  by  a  thick  ring 
of  fibrous  tissue.  This  is  morbid  and  is  due  to  perivascular  disease  having  caused  morbid 
fibroid  deposit. 

FIG.  87. — DISEASED  BLOOD-VESSELS  OF  LUNG.     (X  105.) 

From  a  man  sixty-four  years  old  who  died  of  rapid  phthisis,  h,  h,  the  diseased  blood- 
vessels ;  the  walls  are  thickened  and  the  tissue  forming  them  hangs  in  festoons  in  the  lumina. 
It  is  more  like  epithelium  than  like  the  ordinary  tissue  of  blood-vessel  walls.  These  vessels 
are  like  that  shown  by  Fig.  72.  c,  c,  c,  capillaries,  of  which  there  are  many  more  than  the 
three  indicated,  for  the  tissue  is  very  vascular.  /,  pleura,  which  is  thickened  and  less  dis- 
tinctly defined  from  the  lung-tissue  below  than  is  natural.  Its  deeper  layers  contain  many 
capillaries. 


FIG.  86. 


FIG.  87. 


:>»': "I '».--' i,:->  V-,.   '•'  f*:  '>'^-=" 


THE  BLOOD-VESSELS  OF  THE  LUNGS  103 

fibrous  tissue  was  growing,  as  it  always  does  grow  in  the  lungs  of 
those  who  are  suffering  with  phthisis  unless  it  is  of  the  most  rapid 
character  ;  and  such  was  not  the  case  in  this  instance,  for  it  was  one  of 
the  kind  of  cases  in  which  the  growth  of  blood-vessels  is  exuberant 
and  in  which  the  tissue  of  the  lung  becomes  more  dense.  Some  of 
the  blood-vessels  (c,  c,  <:)  are  of  good  size  and  there  are  a  great  many 
of  them,  but  those  of  this  character  are  without  three  coats,  their 
walls  being  composed  entirely  of  fibrous  tissue,  and  they  are  more  or 
less  thick  according  to  their  size.  The  walls  of  the  largest  blood- 
vessels of  this  class  appear  to  be  exactly  like  those  of  the  smallest 
capillaries  except  for  the  difference  of  their  thickness.  Such  vessels 
are  probably  of  recent  development,  and  they  are  common  in  inflamed 
tissues  and  in  all  sorts  of  growths,  whether  they  be  what  are  called 
new  growths  or  hyperplasias.  The  important  feature,  however,  of 
Fig.  87  is  observed  in  the  two  blood-vessels  h,  /i,  and  it  is  to  show  them 
that  the  drawing  was  made.  They  are  probably  veins,  for  the  one  of 
them  to  the  right  has  shreds  of  muscular  tissue  scattered  in  the  outer 
portion  of  its  wall,  which  has  the  peculiar  character  of  that  shown  by 
Fig.  34,  and  I  have  never  seen  the  muscularis  of  an  artery  like  it. 
The  walls  are  thickened  and  the  tissue  hangs  in  festoons. 

The  appearance  of  the  walls  of  these  two  veins  is  precisely  similar 
to  that  shown  by  Fig.  72,  which  is  from  the  heart.  Such  disease, 
and  it  is  not  at  all  rare,  has  at  least  two  striking  peculiarities  of 
which  I  have  not  been  able  to  find  any  published  description.  These 
are,  first,  that  the  tissue  of  which  the  thickened  walls  are  principally 
composed  is  not  like  any  normal  tissue,  and,  second,  that  there  are  cells 
in  it  that  present  a  peculiar  appearance  which  I  have  never  seen  in 
normal  tissue.  This  more  nearly  resembles  epithelium  than  any  other 
one  of  the  normal  tissues.  The  difference  is  not  easy  to  describe,  but 
is  easy  to  recognize  in  properly  prepared  sections,  and  I  think  it  is  well 
shown  by  Figs.  87  and  72,  as  well  as  by  others  that  I  have  published, 
especially  by  Figs.  21  to  27  in  the  "Origin  of  Disease."  The  pecu- 
liarity of  the  cells  is  that  they  are  large  and  are  generally  composed  of 
a  central  nucleus  and  a  distinct  external  envelope  with  a  space  between 
which  is  filled  by  some  sort  of  solid  or  fluid  which  did  not  stain.  The 
appearance  is  very  curious,  and  it  is  easily  seen  ;  there  is  a  sharply 
defined  external  ring  within  which  is  an  empty  space  except  for  the 
nucleus,  that  is  generally  situated  in  the  centre,  but  is  sometimes  at  one 


104  HUMAN  BLOOD-VESSELS 

side.  In  the  preparation  of  Fig.  87  sufficient  amplification  was  not 
used  to  show  the  peculiarities  of  the  cells,  but  they  are  well  shown  by 
Figs.  21  and  22,  "Origin  of  Disease,"  and  they  are  described  at  page 
52  of  that  work.  In  that  case  the  blood-vessels  described  were  almost 
certainly  of  recent  development,  for  they  were  found  in  the  anterior 
flap  of  the  mitral  valve  of  a  youth  fourteen  years  old  who  died  of 
organic  heart  disease.  In  the  natural  condition  there  are  few  if  any 
blood-vessels  in  the  denser  portions  of  the  fibrous  tissue  of  the  mitral 
valve  flaps. 

The  study  of  the  blood-vessels  of  the  lungs  is  somewhat  unsatisfactory 
because  it  is  inconclusive,  and  especially  because  at  the  present  time  it 
is  impossible  to  obtain  blood-vessels  from  which  to  make  a  set  of  illus- 
trations to  show  an  exact  standard  of  normal  adult  human  lung.  It  is 
to  be  hoped  that  the  day  is  not  distant  when  lung  blood-vessels  known 
to  be  normal  will  be  obtained  and  drawings  of  them  will  be  pub- 
lished. On  the  other  hand,  it  cannot  justly  be  said  that  this  study  has 
been  without  profit,  for  a  number  of  curious  and  important  questions 
connected  with  disease  have  been  discussed  and  elucidated  and  some- 
thing has  been  accomplished  toward  adding  to  the  sum  of  knowledge 
of  the  anatomy  of  the  blood-vessels  of  the  lung.  It  may  be  not  un- 
profitable, in  conclusion,  to  review  briefly  the  salient  points  that  have 
been  under  consideration.  The  presence  of  capillaries  in  the  lining  of 
a  bronchiole,  so  that  they  are  entirely  uncovered  upon  the  inner  sur- 
face of  the  tube,  is  shown  by  one  illustration.  This  is  a  curious  result 
of  disease,  and  it  must  have  important  effects,  and  is  probably  of  ex- 
tremely common  occurrence  I  do  not  remember  to  have  encountered 
any  mention  of  this  phase  of  disease  in  any  publication. 

The  escape  of  blood  from  the  capillaries  of  the  lungs  into  the  air- 
sacs  is  generally  the  last  act  of  the  drama  of  life,  and  it  is  a  process 
which  is  as  yet  quite  beyond  the  reach  of  comprehension.  The 
illustration  showing  a  pulmonary  air-space  which  was  probably 
enlarged  by  emphysema  and  is  only  partially  filled  with  blood,  but 
surrounded  by  lung-tissue  overwhelmed  by  exuded  blood-corpuscles, 
seems  to  indicate  that  emphysema  may  sometimes  be  conservative  of 
life.  For  it  must  be  that  the  walls  of  the  air-sacs,  if  they  become 
stiffer  and  denser  under  the  influence  of  morbid  fibrosis,  are  less  prone 
to  permit  the  escape  of  blood  from  the  capillaries.  If  it  be  granted 
that  my  illustration  (Fig.  83)  and  my  statement  that  I  have  seen 


THE  BLOOD-VESSELS  OF  THE  LUNGS  105 

other  similarly  thickened  capillaries  prove  that  the  walls  of  the  capil- 
laries of  the  lungs  become  materially  thicker  in  chronic  disease,  the 
observation  is  an  important  one,  for  I  know  of  nothing  as  yet  on 
record  which  demonstrates  this  disease  so  that  it  can  easily  be  seen  by 
every  one.  If  the  walls  in  the  capillaries  of  lungs  that  have  undergone 
morbid  fibroid  degeneration  are  thicker  than  normal,  and  the  walls  of 
the  air-sacs  are  thicker,  and  if  besides  this  my  contention  is  correct  that 
the  capillaries  are  evanescent,  and  come  and  go  in  the  tissues  according 
to  the  need  for  them,  then  it  must  be  that  the  number  of  them  is  less 
in  fibroid  lungs,  for  capillaries  would  certainly  be  less  easily  channelled 
out  in  dense  fibroid  tissue  than  in  soft  and  elastic  and  open-meshed 
tissue. 

The  demonstration  of  perivascular  and  peribronchial  fibrosis  is 
curious  and  important,  although  it  is  impossible  at  present  to  say 
whether  the  disease  should  be  classed  as  one  of  the  blood-vessels  or 
of  the  connective  tissue ;  much  less  is  it  possible  to  say  whether  the 
lesion  is  causative  of  disease  or  is  its  consequence.  The  discovery  by 
Gull  and  Sutton  of  the  disease  that  they  named  arteriocapillary  fibrosis 
marked  an  important  advance  of  pathology,  but  it  has  always  seemed 
to  me  that  some  of  their  reasons  are  inconclusive,  and  especially  that 
their  illustrations  fail  to  show  what  was  plain  to  them  in  their  micro- 
scopical preparations.  My  illustrations  of  morbid  fibroid  tissue 
around  arteries  and  veins,  and  of  fibroid  thickening  of  capillaries,  are 
probably  instances  of  the  disease  described  by  Gull  and  Sutton. 
Their  demonstration  of  fibrosis  of  capillaries  was  veiy  imperfect,  if 
not  a  failure.  It  is  astonishing,  and  highly  creditable  to  their  acumen 
as  observers,  that  they  should  have  been  able  to  go  so  much  further  in 
their  conclusions  than  their  illustrations  clearly  demonstrated.  It  is 
generally  the  case  that  those  who  make  microscopical  investigations 
can  satisfy  themselves  and  are  able  to  form  opinions  in  regard  to 
things  they  have  seen  which  at  first  they  are  unable  to  demonstrate 
to  others  by  pictures.  It  must  be  very  rarely  that  a  question  of 
importance  can  be  determined  from  a  single  microscopical  preparation 
and  an  illustration  made,  but  conclusions  are  reached  which  are  cor- 
rect by  seeing  a  little  at  one  time  and  a  little  at  another. 

The  demonstration  of  the  existence  of  very  numerous  new  blood- 
vessels in  phthisical  lung  is  curious,  but  is  no  more  than  might  be 
expected  and  that  is  well  known  to  occur.  Anything  that  causes 


io6  HUMAN  BLOOD-VESSELS 

such  rapid  proliferation  of  cells  and  so  great  tissue  growth  as  occurs 
at  certain  stages  and  in  certain  forms  of  phthisis  must  cause  the  for- 
mation of  new  blood-vessels.  Endarteritis  is  a  disease  that  has  been 
very  extensively  studied  of  recent  years,  but  comparatively  little  atten- 
tion has  been  bestowed  upon  endophlebitis.  A  type  of  this  latter  disease 
is  shown  by  Figs.  34  and  35.  The  effects  of  these  curious  changes 
of  the  lining  of  the  arteries  and  veins  are  not  yet  known,  but  they 
must  be  important.  The  redundant  growth  of  the  intima  shown  by 
Fig.  87  is  most  singular,  and  it  is  very  common.  Morbid  prolifera- 
tion of  the  intima,  called  endarteritis,  is  the  most  common  disease  to 
which  arteries  are  liable,  and  there  is  good  reason  to  think  that  en- 
dophlebitis also  is  of  much  more  frequent  occurrence  than  has  here- 
tofore been  supposed.  The  tissue  which  composes  these  morbid 
thickenings  of  the  lining  of  blood-vessels  is  quite  unlike  any  normal 
tissue,  and  I  have  not  been  able  to  find  any  adequate  published  de- 
scription of  it  nor  any  explanation  of  its  cause.  The  lungs  I  believe 
to  be  the  most  liable  of  all  the  human  organs  to  disease. 


CHAPTER    X 

THE  BLOOD-VESSELS  OF  THE  LIVER 

THE  liver  is  not  of  such  simple  structure  as,  for  instance,  the  heart 
and  kidney,  and  its  anatomy  is  not  so  well  known  as  it  some  day  will 
be.    .Although  the   intimate   connections  of  the  capillaries  with  the 
columns  of  secreting  cells,  and  the  general  course  of  the  hepatic  arte- 
ries and  of  the  portal  and  hepatic  veins  and  the  bile-ducts  are  well 
known,  it  cannot  be  justly  claimed  that  the  exact  relations  of  the 
capillaries  to  the  columns  of  secreting  cells  are  perfectly  understood. 
Nor  is  it  certain  whether  the  blood  ever  comes  directly  in  contact  with 
the  secreting  cells  of  the  liver  without  an  intervening  capillary  wall  in 
the  way  that  it  is  thought  by  some  of  the  most  distinguished  author- 
ities that  the  blood  bathes  the  cells  in  the  pulp  of  the  spleen.     The 
fibrous  framework  that  constitutes  the  skeleton  of  the  liver  and  forms 
the  support  for  the   trabeculae    of   secreting   cells  is   quite    strongly 
made.     This  may  be  seen  in  well-prepared  sections  of  what  is  called 
"nutmeg  liver," — a  subject  that   I    discussed    in   my  book    on  the 
"Origin  of  Disease,"  at  page  102,  and  demonstrated  by  Figs.  71,  72, 
and  73,  and  others  in  that  work.     The  density  of  the  fibrous  framework 
is  well  shown  by  Fig.  72,  and  the  appearances  there  represented  make 
it  difficult  to  believe  that  the  capillaries  always  have  a  distinct  wall  of 
their  own  to  prevent  the  blood  coming  directly  into  contact  with  the 
secreting  cells.     That  drawing  seems  to  me  to  suggest  that  there  is 
not  always  a   separating    capillary  wall  between  the  blood  and  the 
secreting  cells.     It  must  be  remembered,  however,  that  the  illustration 
was  made  from   diseased   tissue,   and  it  is  impossible  to  be  certain 
whether  the  normal  conditions  are  ever  similar  to  those  there  repre- 
sented.     My  previously  published  description  ("Origin  of  Disease") 
of  this  condition  seems  to  me  to  be  somewhat  inadequate  in  several 
respects,  and  especially  in  this  :  that  it  does  not  sufficiently  emphasize 
the  fact  that  the  ordinary  anatomical  descriptions  do  not  make  plain 
how  strong  and  distinctive  a  structure  is  the  fibrous  framework  which 
constitutes  the  skeleton  of  the  liver.      There  can  be  little  doubt  that 
something  still  remains  to  be  learned'regarding  the  anatomy  of  the  liver. 

107 


io8  HUMAN  BLOOD-VESSELS 

It  has  been  impossible  for  me  to  obtain  a  set  of  normal  blood- 
vessels of  the  liver  from  which  to  have  drawings  made,  just  as  it  was 
impossible  to  obtain  such  a  set  of  blood-vessels  from  human  lungs. 
A  knowledge  of  the  natural  histological  appearances  of  the  blood- 
vessels of  adult  human  liver  cannot  be  obtained  from  the  study  of 
existing  publications.  So  much  of  what  is  known  has  been  learned 
from  the  examination  of  the  tissues  of  the  lower  animals  that  it  is 
often  very  difficult  or  impossible  for  any  one  studying  the  subject  to 
know  whether  particular  blood-vessels  are  diseased  or  healthy,  because 
there  is  no  accepted  standard  of  the  normal  to  which  to  turn  to  decide 
the  question.  It  is  very  probable  that  through  the  continued  study 
of  the  pathology  of  the  liver  a  great  deal  may  be  learned  of  its 
anatomy,  for  even  in  pathological  tissues  some  of  the  blood-vessels  are 
not  diseased. 

Fig.  88  shows  a  section  of  a  portal  vein  and  surrounding  vessels 
of  the  liver  of  a  man  twenty-three  years  old  who  died  of  empyema. 
The  large  portal  vein  which  occupies  the  centre  is  partially  filled 
by  clot,  and  in  the  fibrous  tissue  with  which  it  is  surrounded  there 
are  bile-ducts  and  branches  of  the  hepatic  artery  as  well  as  other 
openings  which  are  probably  smaller  branches  of  the  portal  vein. 
The  group  is  such  an  one  as  it  is  most  common  to  find  in  specimens 
of  human  liver  that  are  obtained  in  the  course  of  any  routine  series 
of  post-mortem  examinations.  I  am  unable  to  recognize  that  these 
blood-vessels  are  diseased,  and  yet  they  are  not  at  all  like  what  the 
ordinary  anatomical  teachings  would  lead  us  to  believe  to  be  normal. 
The  wall  of  the  large  portal  vein  is  composed  of  nothing  but  fibrous 
tissue  without  the  slightest  approach  to  any  division  into  three  coats, 
and  the  walls  of  the  branches  of  the  hepatic  artery  are  thick.  This 
latter  may  be  due  to  shrinkage  m  the  course  of  preparation  for  section, 
or  it  may  be  that  it  is  common  for  the  minute  arterioles  in  human 
adult  tissues  to  be  much  thicker  walled  than  ordinary  anatomical 
descriptions  teach.  Something  of  what  has  been  described  can  be 
seen  in  the  drawing,  but  greater  amplification  is  required  to  make  it 
possible  fully  to  recognize  the  details  of  structure.  When  more  highly 
magnified  the  section  distinctly  shows  what  has  been  asserted  regarding 
the  blood-vessels.  This  drawing,  which  is  of  a  kind  that  is  very 
common  to  find,  shows  how  it  is  often  difficult  to  decide  whether  a 
tissue  is  diseased  or  normal,  and  at  the  same  time  it  emphasizes  my 


FIG.  88. — CROSS-SECTION  OF  A  PORTAL  VEIN  AND  OF  OTHER  VESSELS  IN  THE  CAPSULE 

OF  GLISSON.     (X  24.) 

From  a  man  of  twenty-three  who  died  of  empyema.  The  portal  vein,  hepatic  arteries, 
and  bile-ducts  are  fairly  representative  of  such  vessels  as  they  are  found  in  adults.  They  are, 
however,  quite  different  in  appearance  from  the  ordinary  pictures  in  text-books  of  histology. 


FIG. 


THE  BLOOD-VESSELS  OF  THE   LIVER  109 

statement  that  it  is  very  desirable  that  a  standard  of  the  normal  of  the 
hepatic  blood-vessels  should  be  obtained. 

Fig.  89  depicts  a  group  of  vessels  of  the  liver  of  a  man  sixty-two 
years  old  who  died  of  hepatic  cirrhosis.  In  the  centre  is  a  good-sized 
portal  vein  which  is  cut  across.  Above  this,  to  the  left,  is  a  smaller 
portal  vein  which  has  very  thick  walls,  and  to  the  right,  above  the  large 
portal  vein,  is  a  thick-walled  hepatic  artery.  A  striking  feature  of  the 
disease  is  that  in  the  walls  both  of  the  large  portal  vein  and  of  the 
smaller  thick-walled  one  there  are  many  minute  new-formed  blood- 
vessels. Greater  amplification  brings  out  details  of  structure  which 
are  not  shown  by  the  drawing,  but  this  exhibits  the  most  important 
features.  The  new  blood-vessels  are  very  numerous  in  the  thickened 
wall  of  the  smaller  portal  vein,  which  is  above  and  to  the  left,  and 
they  are  of  the  nature  of  capillaries  with  thin  walls  of  fibrous  tissue,  as 
it  has  already  been  shown  that  new  vessels  are  when  they  are  first 
developed  and  are  still  small.  The  thickening  of  the  wall  of  the  hepatic 
artery  is  mostly,  if  not  entirely,  due  to  unnatural  growth  of  the  intima, 
although  it  may  be  that  the  muscularis  is  slightly  thickened.  The  wall 
of  the  large  portal  vein  is  probably  somewhat  thicker  than  normal  and 
there  are  a  good  many  vessels  in  it,  some  of  which  are  almost  cer- 
tainly of  new  growth.  Altogether  the  drawing  shows  a  typical  example 
of  what  might  be  expected  to  occur  in  cirrhosis  of  the  liver,  a  disease 
of  which  the  most  important  feature  is  the  growth  of  fibrous  tissue. 
There  is  much  more  fibrous  tissue  in  the  portal  channel  than  is  nor- 
mal, and  all  of  the  blood-vessels  except  those  of  new  growth,  which 
were  lately  developed  to  nourish  the  increase  of  tissue,  are  thick  walled. 
It  is  curious  that  the  tissue  composing  the  thickened  portal  vein  is 
purely  fibrous,  there  being  no  division  into  different  coats,  while  the 
thickened  hepatic  artery  has  three  distinct  tunics  and  it  is  the  intima 
which  is  thickened.  Endarteritis  of  this  form  is  the  commonest  of  all 
known  diseases  of  the  blood-vessels,  as  has  already  so  often  been  said, 
and  it  is  singular  that  the  diseased  hepatic  artery  and  portal  vein 
which  lie  so  close  together,  and  are  therefore  by  their  contiguity 
exposed  to  the  same  influences,  should  both  be  thick  walled,  but  that 
the  nature  of  the  thickening  should  be  so  entirely  different.  It  is 
at  present  impossible  to  know  whether  this  condition  is  due  to  a 
single  cause  which  within  a  small  area  operated  differently,  and  so 
as  to  produce  different  results  upon  the  portal  vein  and  the  hepatic 


no  HUMAN  BLOOD-VESSELS 

artery,  or  if  there  were  two  separate  causes  of  disease.  Another 
strange  and  curious  fact  often  observed  in  cases  of  disease  of  blood- 
vessels (which  is  shown  by  the  drawing)  is  that  where  arteries  or  veins 
lie  close  together  one  may  be  greatly  diseased  while  the  other  remains 
healthy,  or  even  one  portion  of  the  same  blood-vessel  may  be  much 
diseased  while  another  part  close  by  is  quite  normal.  The  large  portal 
vein  in  the  centre  of  Fig.  89  is  but  little  thickened,  while  the  small 
one  to  the  left  and  above  it  is  so  thick  walled  that  its  lumen  is  almost 
closed,  and  yet  the  two  are  in  contact  and  the  smaller  is  probably  a 
branch  of  the  larger  one. 

Fig.  90  shows  a  section  of  the  anterior-inferior  edge  of  the  liver  of 
a  man  sixty  years  old  who  died  of  dilatation  of  the  heart.  The  knife- 
like  sharpness  of  the  edge  of  the  liver,  and  the  fluting  of  its  margin, 
were  easily  distinguished  with  the  unaided  eye  at  the  autopsy,  and  it 
is  almost  certain  therefore  that  they  had  existed  during  life  and  were 
not  the  result  of  post-mortem  shrinkage.  The  capsule  is  thickened 
and  the  greatest  proportion  of  the  liver  included  in  the  illustration  is 
composed  of  fibrous  tissue,  although  there  is  quite  a  good  deal  that 
is  formed  of  the  secreting  cells.  This  is  plainly  shown  by  the  drawing, 
but  of  course  it  is  possible  to  make  a  much  nicer  distinction  between 
the  different  kinds  of  tissue  if  the  section  is  examined  more  highly 
magnified.  The  most  striking  feature  of  all,  however,  is  the  extreme 
and  unnatural  multiplicity  of  the  blood-vessels.  Most  of  these  lie  in 
the  morbid  fibrous  tissue  and  are  not  surrounded  by  normal  liver.  It 
is  impossible  to  be  certain  whether  the  vessels  were  newly  developed 
or  are  the  natural  blood-vessels  squeezed  together  by  the  condensa- 
tion and  shrinkage  caused  by  the  growth  and  contraction  of  the 
fibrous  tissue.  It  is  most  probable  that  the  original  vessels  are  still 
present  and  have  been  pressed  more  nearly  together  than  they  were 
before  the  liver  became  diseased,  but  it  is  almost  certain  that  some  of 
the  blood-vessels  here  are  new.  This  opinion  is  supported  by  the 
facts  that  many  of  them  have  the  appearance  of  new  vessels  and  that 
the  blood-vessels  here  are  too  numerous  for  it  to  be  possible  that  they 
are  nothing  but  the  natural  ones.  The  subject  of  the  development  of 
new  blood-vessels  in  adult  tissues  is  a  very  important  one  and  it  is  dis- 
cussed in  Chapter  III  of  this  work  and  in  Chapter  IV  of  my  book  on 
the  "Origin  of  Disease."  Figs.  15,  18,  19,  20,  and  21  in  that  work 
represent  blood-vessels  in  various  stages  of  growth  and  they  are  almost 


FIG.  89. — THICKENING  OF  A  PORTAL  VEIN  AND  HEPATIC  ARTERY.    -(X  24.) 

From  a  man  sixty-two  years  old  who  died  of  cirrhosis  of  the  liver.  A  section  of  the 
liver.  The  large  space  is  the  calibre  of  a  portal  vein  containing  some  blood.  Above  it  to 
the  left  is  the  thick-walled  portal  vein,  and  in  its  walls  are  many  new  blood-vessels.  To  the 
right  of  this  thick  portal  vein  is  an  hepatic  artery,  which  is  also  thick-walled.  The  intima 
especially  is  thickened. 

FIG.  90. — ANTERIOR-INFERIOR  EDGE  OF  A  CIRRHOTIC  LIVER  AND  BLOOD-VESSELS.  . 

(X20.) 

From  a  man  of  sixty  years  who  died  of  dilatation  of  the  heart.  The  puckering  of  the 
hepatic  tissue  and  fluted  appearance  of  its  edge  were  easily  seen  with  the  naked  eye  when  the 
post-mortem  examination  was  made.  The  greatest  part  of  the  tissue  is  fibrous,  but  a  good 
deal  of  liver-tissue  still  remains.  The  number  of  blood-vessels  crowded  in  the  space  is  very 
great,  and  it  is  impossible  to  ascertain  how  many  of  them  are  new  vessels  and  how  many  are 
the  natural  vessels  squeezed  together  by  the  shrinkage.  Many  of  the  blood-vessels  are  very 
thick-walled  owing  to  disease,  and  there  is  one  large  one  and  other  smaller  ones  of  which 
the  lumina  are  nearly  closed. 


FIG.  89. 


- /v  W  -7^:25 


FIG.  90. 


THE  BLOOD-VESSELS  OF  THE  LIVER 


in 


surely  due  to  a  new  development  of  tissue.  Fig.  1 5  is  a  pair  of  im- 
perfect blood-vessels  in  the  wall  of  an  aneurism,  and  Fig.  2 1  is  a  ves- 
sel in  the  thickened  and  diseased  anterior  leaflet  of  the  mitral  valve. 
These  are  in  many  respects  like  the  large  thick-walled  vessel  with  a 
very  small  lumen  shown  in  the  centre  of  the  drawing  Fig.  90,  and  of 
some  of  the  other  smaller  ones  which  are  scattered  around  it.  The 
largest  one  when  it  is  examined  with  greater  amplification  distinctly 
shows  the  plicated  membrane.  Whether  this  is  a  certain  indication 
that  it  was  a  natural  vessel  which  became  thickened  and  nearly  closed 
owing  to  disease,  or  if  the  vessel  is  purely  a  new  development,  it  is  im- 
possible at  present  to  ascertain.  After  having  examined  a  great  many 
such  vessels  in  various  kinds  of  tissues,  my  own  conclusion  is  that  it 
is  often  very  difficult  to  decide  when  studying  any  particular  one 
whether  it  is  a  new  growth  or  if  it  is  only  one  which  was  once  normal 
and  has  become  changed  and  distorted  by  disease.  The  drawing  also 
shows  other  and  thin-walled  vessels,  such  as  commonly  develop  in  new 
and  proliferating  tissues.  The  details  of  this  are  easily  seen  if  the 
section  is  examined  with  greater  amplification. 

Fig.  90,  like  Fig.  89,  is  beyond  question  a  type  of  cirrhosis  of  the 
liver,  although  the  case  was  classified  clinically  as  one  of  death  from 
dilatation  of  the  heart.  The  combination  of  a  greater  or  less  degree  of 
fibrosis  of  the  liver  with  organic  heart  disease  is  so  usual  that  it  may 
in  the  majority  of  instances  be  expected  to  be  present.  A  number  of 
striking  and  peculiar  lesions  of  cirrhosis  are  exhibited  by  the  drawing. 
There  is  a  very  great  amount  of  morbid  fibrous  tissue  which  has 
replaced  a  corresponding  amount  of  liver  substance.  The  number 
of  blood-vessels  that  exist  in  so  small  a  piece  of  liver  is  extraordinary, 
and  most  of  them  are  in  the  morbid  fibrous  tissue  and  not  in  the 
natural  tissue  of  the  liver  that  remains.  The  blood-vessels  are  both 
of  the  thin-walled  variety  that  are  always  found  in  new  and  prolifer- 
ating tissues,  and  which  are  certainly  of  new  development,  and  of  the 
thick -walled  nature  which  also  are  generally  found  in  new  and  prolifer- 
ating tissue  but  in  regard  to  which  it  is  impossible  at  present  to  decide 
whether  they  are  of  new  development  or  are  natural  vessels  changed 
and  distorted  by  disease.  The  thickness  of  the  fibrous  capsule  and 
the  manner  in  which  the  whole  of  the  surface  of  the  liver  that  is  shown 
in  section  is  fluted  are  very  striking,  and  more  striking  still  perhaps  is 
the  sharp  knife-like  form  which  was  assumed  by  the  anterior-inferior 


ii2  HUMAN  BLOOD-VESSELS 

edge  of  the  liver,  which  is  distinctly  shown  by  the  drawing.  It  is  to 
be  recollected  that  these  two  features — the  knife-like  sharpness  of  the 
edge  of  the  liver  and  the  puckering  of  the  surface — were  easily  distin- 
guished with  the  unaided  eye  at  the  post-mortem  examination,  and 
that  they  had  therefore  almost  certainly  existed  during  life.  They  con- 
stitute a  striking  example  of  the  effects  produced  by  the  tendency 
of  morbid  fibroid  tissue  constantly  and  progressively  to  shrink  and  to 
cause  distortion.  In  conclusion,  it  may  be  not  without  advantage  to 
repeat  that  the  minute  anatomy  of  the  liver  is  still  only  imperfectly 
known,  and  that  it  is  greatly  to  be  hoped  that  the  time  may  not  be  far 
distant  when  an  exact  knowledge  will  be  obtained  of  the  standard  of 
what  is  normal  in  the  blood-vessels  of  the  human  liver. 


CHAPTER    XI 
THE  BLOOD-VESSELS  OF  THE  SPLEEN 

THERE  is  less  known  of  the  anatomy  and  of  the  function  of  the 
spleen  than  of  any  other  of  the  great  organs.  It  is  classified  as  be- 
longing to  the  system  of  lymph-glands,  and  it  is  very  probable  that  it 
has  to  do  with  the  production  or  with  the  destruction  of  the  blood- 
corpuscles,  but  neither  of  these  things  is  certain.  Nor  is  the  anatomy 
of  the  spleen  well  understood.  The  organ  consists  of  fibrous  tissue, 
of  lymph-cells,  and  of  lymph-  and  blood-vessels.  The  fibrous  tissue 
forms  the  capsule,  which  covers  the  entire  surface  of  the  organ  ;  the 
trabeculae,  some  of  which  are  quite  large  and  strong  and  of  compli- 
cated structure  ;  and  the  reticulum,  which  supports  the  lymph-cells. 
The  fibrous  tissue  of  the  spleen  contains  many  connective-tissue  cor- 
puscles and  these  cells  are  of  an  infinite  variety  of  forms.  As  the 
connective-tissue  cells  of  the  spleen  are  of  such  varied  appearance, 
and  as  the  lymph-cells  also  are  liable  to  differ  greatly  under  differing 
circumstances,  it  can  readily  be  understood  that  cells  varying  much  in 
appearance  are  found  in  the  spleen.  The  exact  manner  in  which  the 
lymph-cells  are  supported  by  the  fibrous  reticulum  and  their  relations 
to  each  other  are  not  understood  in  the  same  way,  for  instance,  as  the 
mutual  relations  of  the  epithelium  and  connective  tissue  of  the  kidney 
and  those  of  the  muscular  and  fibrous  tissues  of  the  heart  are  known. 
The  experiment  of  treating  spleen  tissue  with  a  reagent  which  will 
partially  disintegrate  it,  and  then  washing  it  to  remove  the  lymph-cells, 
has  been  made.  The  material  that  remains  after  such  treatment  can 
be  seen  with  the  microscope  to  consist  of  a  fine  fibrous  reticulum 
in  which  the  lymph-cells  were  supported.  This  test,  however,  al- 
though very  interesting  and  instructive,  is  rather  crude,  and  does  not 
demonstrate  anything  that  had  not  already  been  learned  by  the  ex- 
amination of  sections  and  even  by  the  older  and  still  coarser  methods 
of  microscopical  examination.  It  is  in  the  highest  degree  improbable 
that  the  pulp  of  the  spleen  consists  of  a  reticulum  which  is  without 
orderly  arrangement,  in  which  the  lymph-cells  are  irregularly  distrib- 
uted as  a  handful  of  seeds  might  be  if  they  were  thrown  into  a  tangle 
8  "3 


ii4  HUMAN  BLOOD-VESSELS 

of  loose  hay.  The  splenic  reticulum  is  almost  certainly  developed 
according  to  some  simple  system,  and  even  in  adult  tissues  it  probably 
is  still  a  well-organized  structure,  and  it  is  equally  probable  that  in 
this  the  lymph-cells  are  disposed  in  a  manner  which  is  as  orderly  as 
that  of  the  columns  of  secreting  cells  of  the  liver  or  of  the  epithe- 
lium of  the  kidney.  The  very  word  "pulp,"  which  is  commonly 
employed  to  designate  the  tissue  which  composes  the  substance  of 
the  spleen,  is  significant  of  the  present  lack  of  understanding  of  the 
anatomy  of  the  organ.  Imagine  an  anatomist  speaking  of  the  tissues 
of  the  heart,  liver,  or  kidney,  which  structurally  are  so  beautiful,  as 
pulp  ! 

The  lymph-vessels  of  the  spleen  are  so  little  understood  that  it  is 
not  worth  while  here  to  try  to  describe  them.  The  blood-vessels 
are  the  subject  of  the  chapter,  and  much  that  is  final  regarding  them 
is  already  known,  but  on  the  other  hand  a  great  deal  remains  still  to 
be  learned.  There  are  capillaries  in  the  spleen  just  as  there  are  capil- 
laries in  most  other  tissues,  and  these  can  easily  be  seen  in  well-made 
preparations.  It  has,  however,  been  very  generally  taught  that  the 
circulation  of  the  spleen  is  different  from  that  of  other  organs,  in  that 
the  blood  is  not  always  confined  within  arteries,  veins,  and  capillaries, 
but  that  under  natural  conditions  in  the  pulp,  both  the  corpuscles  and 
the  liquor  sanguinis  of  the  blood  pass  unconfined  by  any  blood- 
vessel wall  into  the  reticulum  and  among  the  lymph-cells.  If  it  is 
natural  for  the  blood  of  the  spleen  to  come  in  direct  contact  with  the 
lymph-cells,  and  for  the  corpuscles  and  liquor  sanguinis  to  pass  freely 
among  and  around  them,  it  is  necessary  to  conceive  of  a  structure  quite 
different  from  that  of  any  of  the  other  organs  and  tissues.  Even  to 
imagine  such  a  structure  is  difficult,  for  its  existence  would  neces- 
sitate the  absence  of  connective  tissue,  and  the  absence  of  connective 
tissue  from  any  one  of  the  softer  tissues,  which  is  their  only  sup- 
porting framework,  would  involve  chaos.  It  is  absolutely  impossi- 
ble to  believe  that  the  spleen  tissue  in  any  part  of  the  organ  can 
be  of  such  a  nature  as  to  form  a  pulp  constituted  of  a  mixture  of 
lymph-cells,  blood-corpuscles,  and  liquor  sanguinis — just  as  good- 
sized  pebbles,  fine  sand,  and  water  might  be  mixed  in  a  bowl. 
The  circulation  of  the  blood  has  been  studied  to  its  most  minute 
details  and  its  mysteries  unravelled  in  the  transparent  tissues  of 
some  of  the  lower  animals,  and  nothing  has  been  seen  to  support 


THE  BLOOD-VESSELS  OF  THE  SPLEEN  115 

the  view  that  the  blood  ever  normally  escapes  from  the  restraint  of 
the  walls  of  the  blood-vessels.  The  circulation  when  studied  in  the 
lower  animals  shows  the  blood  flowing  within  the  walls  of  the  vessels, 
and  it  is  only  under  the  influence  of  morbid  conditions — like  irrita- 
tion and  inflammation — that  it  can  be  seen  to  escape  into  the  tissues. 
It  is  not  necessary  to  tell  here  at  length  how  the  blood-corpuscles 
flow  slowly  at  the  periphery  and  more  rapidly  in  the  middle  of  the 
stream  in  a  capillary  which  lies  within  a  portion  of  tissue  that  becomes 
inflamed,  and  how  then  the  white  cells  squeeze  out  through  the  mem- 
branous wall  of  the  capillary  and  lie  free  in  the  surrounding  tissue. 
The  instant  effect,  however,  is  disease,  and  tissue  diseased  in  this  way 
never  rests  until  it  has  rid  itself  of  the  effused  blood  or  is  dead.  It 
is  difficult  to  believe  that  it  can  be  normal  for  the  blood  to  flow  through 
the  spleen  without  the  membranous  walls  of  the  capillaries  to  restrain 
it  and  to  guide  its  flow. 

It  might  be  thought  that  the  study  of  injected  specimens  of  adult 
human  spleen  would  decide  this  question  whether  the  blood  flows  in 
the  organ  unconfined  by  any  blood-vessel  wall,  but  I  have  made  such 
preparations  and  have  examined  them  carefully  and  they  throw  no 
light  upon  the  subject.  These  preparations  are  described  at  page  21. 

In  the  injected  preparations  of  spleen  which  show  the  cells  of  the 
organ  surrounded  by  blue  nets,  it  is  certain  that  the  injection  material 
fills  spaces  which  surround  the  cells,  and  that  these  spaces  look  like  a 
system  of  tubes  ;  but  it  is  impossible  to  ascertain  whether  the  spaces 
have  walls  which  separate  the  blue  injection  from  the  cells  or  if  this  lies 
directly  in  contact  with  them.  I  am  thus  driven  back  to  the  conclusion 
that,  although  it  is  a  fact  that  the  blue  injection  is  forced  into  minute 
spaces  around  the  cells,  it  is  impossible  at  present  to  ascertain  whether 
these  are  torn  open  in  the  tissue  by  the  injecting  force,  and  are  therefore 
abnormal,  or  if  they  are  natural  tubes  between  the  cells,  and,  if  they 
are  natural  tubes,  whether  they  have  separate  capillary  walls  of  their 
own  or  are  without  walls.  It  is,  then,  true  that  experiments  made  of 
injecting  the  spleen  do  not  throw  any  light  upon  the  unsolved  problems 
regarding  the  circulation  of  the  blood  in  the  capillaries  of  the  organ. 
Much,  therefore,  still  remains  to  be  learned  of  the  capillaries  of  the 
spleen  and  of  the  ultimate  ramifications  of  the  blood  in  the  organ.  It 
has  been  impossible  for  me  to  obtain  a  set  of  sections  of  arteries  and 
veins  of  the  spleen  from  which  I  could  have  drawings  made  to  show 


u6  HUMAN  BLOOD-VESSELS 

as  types  of  the  normal,  just  as  I  have  been  unable  to  obtain  typically 
normal  blood-vessels  of  the  other  organs.  It  is  a  peculiarity  of  the 
anatomy  of  the  spleen  that  most  of  its  larger  arteries  and  veins  lie  in 
the  trabeculae,  and  are  therefore  surrounded  and  supported  by  fibrous 
tissue. 

Fig.  91  depicts  two  arteries  and  a  vein  in  a  trabecula  of  the  spleen 
of  a  boy  eleven  years  old  who  died  of  acute  peritonitis.  Neither  the 
vein,  which  is  the  central  vessel,  nor  the  arteries,  which  lie  on  either 
side  of  it,  are  like  blood-vessels  that  are  described  as  normal,  and  yet 
all  three  are  fair  types  of  what  it  is  most  common  to  find  in  such 
spleens  as  are  obtained  at  post-mortem  examinations.  In  this  instance 
the  patient  died  of  a  disease  which  affords  no  ground  for  the  assump- 
tion that  there  had  been  latent  vascular  disease  previous  to  the  final 
fatal  attack.  The  vein  is  a  fibrous  ring,  and,  although  it  has  a  some- 
what differentiated  wall  (so  that  it  cannot  be  said  to  be  a  simple  chan- 
nel hollowed  out  in  the  fibrous  tissue  of  the  trabecula),  there  is  nothing 
like  a  division  of  the  wall  into  three  coats,  as  is  said  to  be  normal  in 
veins  of  this  size.  The  arteries,  and  especially  the  larger  of  the  two, 
show  some  thickening  of  the  muscular  coat,  and  the  intima  instead 
of  being  a  thin  layer  of  endothelium  is  quite  thick.  The  appearance 
is  typical  of  what  is  most  common  in  human  spleen  and  in  other 
tissues.  These  arteries  are  more  thick  walled  than  is  normal,  the  in- 
tima being  more  affected  than  the  other  two  coats.  At  the  same 
time,  the  vein  has  not  three  defined  coats,  but  is  formed  purely  of 
fibrous  tissue.  A  peculiar  feature  is  that  there  are  two  arteries  and 
only  one  vein,  whereas  it  is  a  much  more  common  thing  in  most 
tissues  to  find  a  single  artery  with  two  accompanying  veins. 

Fig.  92  shows  the  blood-vessels  in  a  trabecula  of  the  spleen  of  a 
man  forty-eight  years  old  who  died  of  dysentery.  The  central  vessel 
appears  to  be  an  artery  and  the  two  others  to  be  veins.  It  is  quite 
common  to  find  such  vessels  in  the  spleen.  The  walls  of  the  artery 
are  fairly  well  defined,  three  coats  being  distinctly  visible  ;  but  the 
veins  are  merely  openings  in  the  fibrous  trabecula,  there  being  noth- 
ing like  three  coats  and  not  even  a  trace  of  muscular  tissue  distinguish- 
able. It  is  impossible  to  say  whether  the  condition  is  due  to  disease, 
or  if  such  a  departure  from  the  accepted  standard  of  the  normal  can 
be  due  to  the  time  of  life,  for  the  man  was  past  middle  life,  although 
by  no  means  sufficiently  advanced  in  years  to  be  classed  as  old.  It 


FIG.  91. — BLOOD-VESSELS  OF  THE  SPLEEN.     (X  50.) 

From  a  boy  of  eleven  years  who  died  of  acute  peritonitis.  Blood-vessels  in  a  trabecula 
of  the  spleen.  The  large  vessel  in  the  middle  is  a  vein,  and  to  right  and  left  of  it  are  two 
arterioles.  There  is  no  reason  to  suppose  that  the  child  had  suffered  with  disease  of  the 
blood-vessels,  and  yet  neither  the  vein  nor  the  arteries  are  like  the  accepted  standards  of  the 
normal.  The  vein  is  a  tube  of  fibrous  tissue  without  distinct  differentiation  into  three  coats, 
while  both  the  arterioles  have  thick  muscular  coats,  and  their  intimas  are  thicker  than  is  nat- 
ural in  such  small  vessels.  It  is  common  in  pathological  investigations  to  find  the  blood- 
vessels like  these  rather  than  like  the  pictures  in  text-books  which  are  said  to  represent  the 
normal. 


FIG.  92. — THREE  BLOOD-VESSELS  IN  A  SPLEEN  TRABECULA.     (X  50.) 

.From  a  man  of  forty-eight  years  who  died  of  dysentery.  The  central  vessel  is  almost 
certainly  an  artery  and  the  two  others  are  veins.  It  is  common  to  find  vessels  like  the  two 
veins  in  the  spleen.  They  are  almost  without  differentiated  walls,  being  merely  openings 
in  the  fibrous  trabecula.  Neither  intima,  nor  muscularis,  nor  adventitia  can  be  distinguished. 
It  is  impossible  to  say  whether  such  a  condition  is  the  result  of  disease  or  if  it  is  natural  at 
forty-eight  years  of  age. 


FIG.  91. 


FIG.  92. 


THE  BLOOD-VESSELS  OF  THE  SPLEEN  117 

is  unquestionably  true  that  very  considerable  changes  take  place  in 
the  tissues  as  life  advances.  The  two  drawings,  Figs.  91  and  92, 
present  interesting  points  of  similarity  and  of  contrast  In  Fig.  91 
the  walls  of  the  arteries  are  distinctly  thickened,  and  in  Fig.  92  the 
wall  of  the  artery  is  somewhat  ragged,  but  presents  no  striking  de- 
parture from  the  normal.  In  Fig.  91  the  wall  of  the  vein  is  not  di- 
vided into  three  coats,  and  has  no  muscular  tissue  in  it,  but  there  is  a 
fibrous  wall,  differentiated  from  the  tissue  of  the  trabecula  in  which  it 
lies.  In  Fig.  92  the  veins  appear  simply  as  openings  in  the  trabecula, 
there  not  being  anything  like  differentiated  walls  to  serve  as  frames. 
It  might  be  said  that  the  peculiar  appearance  of  the  veins  of  Fig.  92 
is  due  to  faulty  technique  in  preparing  the  section,  that  there  were 
during  life  differentiated  walls  of  the  veins  and  that  they  were  torn 
out  or  dropped  out  in  the  course  of  preparation  of  the  tissue.  This 
tissue,  however,  was  prepared  in  a  manner  exactly  similar  to  that  used 
in  preparing  other  sections,  and  I  do  not  believe  that  anything  was 
lost,  but  that  the  condition  resulted  from  disease.  Pathologists  often 
explain  conditions  that  are  difficult  to  understand  by  saying  that 
they  resulted  from  bad  technique,  and  by  this  evasion  they  fail  to 
recognize  important  truths. 

Fig-  93  is  an  illustration  of  an  arteriole  in  a  trabecula  of  the 
spleen  of  a  man  fifty-four  years  old  who  died  of  Bright' s  disease. 
This  blood-vessel  can  be  certainly  recognized  as  an  arteriole  by  the 
appearance  of  its  muscular  coat.  The  muscular  coat  is  of  compact 
structure  and  forms  a  thin  layer  of  about  even  diameter  around  the 
vessel,  and  inside  this  lies  the  intima  which  is  very  greatly  and 
unevenly  thickened.  I  have  never  seen  the  muscular  layer  of  a  vein 
present  an  appearance  exactly  similar  to  this.  It  is  therefore  reason- 
ably certain  that  the  vessel  is  an  arteriole.  The  disease  that  affects  it 
is  endarteritis  of  the  form  which  has  already  been  said,  in  connection 
with  the  descriptions  of  other  organs  and  tissues,  to  be  the  common- 
est of  all  the  diseases  that  attack  the  blood-vessels.  In  order  to  ap- 
preciate everything  that  is  shown  by  this  arteriole  it  is  necessary  to 
examine  it  with  greater  amplification,  but  most  of  the  characteristics, 
and  certainly  the  most  important  ones,  are  shown  by  the  drawing. 
The  intima  is  greatly  and  irregularly  thickened.  So  irregular  is  this 
thickening  that  the  opening  of  the  vessel  is  unsymmctrically  placed 
instead  of  being  in  the  centre.  If  the  section  is  examined  more 


nS  HUMAN  BLOOD-VESSELS 

magnified  it  can  be  seen  that  many  of  the  cells  which  form  the  intima 
have  the  peculiar  hollowed  appearance  that  is  described  at  page  103 
as  common  in  diseased  intima,  and  which  is  quite  unlike  that  of  any 
normal  cell  or  tissue.  Outside  the  intima  is  the  muscularis,  which,  it 
has  already  been  said,  forms  an  even  circle  of  closely  felted  tissue. 
No  distinction  whatever  can  be  made  out  between  the  adventitia  of 
the  arteriole  and  the  fibrous  tissue  of  the  trabecula  in  which  it  is 
included.  The  spleen  is  an  especially  good  organ  in  which  to  verify 
the  correctness  of  the  assertion  made  at  page  6,  that  arteries  and 
veins  should  be  considered  to  have  only  two  coats — the  intima  and 
muscularis — and  that  what  is  described  as  the  adventitia  should  be 
regarded  as  a  part  of  the  perivascular  connective  tissue  by  which 
all  blood-vessels  are  surrounded.  It  is  always  impossible  to  draw  a 
line  of  distinction  separating  the  perivascular  connective  tissue  from 
the  adventitia,  and  frequently  in  the  spleen — and  unusually  well  in 
this  drawing  of  spleen — it  can  be  seen  that  the  fibrous  tissue  of  the 
trabecula  is  an  even  and  uniform  structure  abutting  directly  against 
the  muscularis  of  the  arteriole.  Sometimes,  as  the  conditions  shown 
by  this  drawing  prove,  the  adventitia  and  the  perivascular  connective 
tissue  are  absolutely  indistinguishable,  but  more  often  sections  of  the 
spleen  present  the  appearance  of  Fig.  91,  which  shows  that  the  fibrous 
tissue  immediately  outside  the  muscularis  of  the  arterioles  is  of  looser 
texture  than  the  rest  of  the  trabecula.  This  trabecula  (Fig.  93)  con- 
tains a  greater  number  of  cells  than  is  usual  in  the  trabeculae  of  the 
spleen,  which,  when  examined  in  sections,  often  appear  to  be  almost 
acellular.  The  morbid  conditions  that  have  been  described  are  ex- 
actly what  might  have  been  expected  a  priori  to  exist  in  the  spleen 
of  a  man  of  fifty-four  who  died  of  Bright's  disease,  for  that  malady 
is  prone  to  cause  fibrosis  and  inflammation  and  disease  of  the  blood- 
vessels. The  most  striking  thing  which  is  shown  by  the  drawing 
is  the  endarteritis,  and  it  can  hardly  be  said  too  often  that  endarteritis 
is  the  commonest  disorder  to  which  the  blood-vessels  are  subject.  It 
occurs  at  all  ages  and  is  found  in  the  tissues  of  persons  dead  of  every 
known  disease,  and  yet  its  extensive  existence  in  the  body  is  not 
incompatible  with  the  continuance  of  good  health. 

Fig.  94  shows  thick-walled  blood-vessels  of  the  spleen  of  a  man 
seventy  years  old  who  died  of  chronic  myelitis,  and  who  had  contracted 
kidneys  and  general  fibrosis  of  many  organs.  There  are  four  blood- 


FIG.  93. — THICKENED  BLOOD-VESSEL  IN  SPLEEN.     (X  50.) 

From  a  man  fifty-four  years  old  who  died  of  Bright' s  disease.  The  blood-vessel  is  prob- 
ably an  arteriole  and  it  lies  in  a  trabecula.  Its  walls  are  thickened  and  its  opening  is  not  in 
the  centre  owing  to  the  irregularity  of  the  thickening.  There  is  a  great  increase  of  the  number 
of  cells  in  the  trabecula  owing  to  the  disease. 

FIG.  94. — FOUR  THICKENED  BLOOD-VESSELS  OF  THE  SPLEEN.     (X  50.) 

From  a  man  seventy  years  old  who  died  of  chronic  myelitis.  It  is  impossible  to  know 
whether  such  thickened  and  diseased  vessels  are  arteries  or  veins ;  but  they  are  more  like 
arteries.  They  all  lie  in  the  fibrous  trabeculse.  The  two  larger  ones  have  thickened  walls 
and  the  muscular  tissue  is  still  easily  seen.  The  greater  part  of  the  wall  is  composed  of  the 
thickened  intima.  The  two  smaller  ones  are  almost  closed. 


FIG.  93. 


FIG.   94. 


THE  BLOOD-VESSELS  OF  THE  SPLEEN  119 

vessels,  two  larger  and  two  smaller  ones,  all  of  which  lie  in  the  trabec- 
ulae,  and  it  is  impossible  to  be  certain  whether  they  are  arterioles  or 
veins,  but  I  believe  them  to  be  arterioles.  These  blood-vessels  are 
affected  by  endarteritis.  The  two  smaller  ones  are  so  thick -walled  that 
their  calibres  are  nearly  obliterated.  The  larger  ones,  especially  the 
upper  of  the  two,  furnish  another  striking  example  of  disease  exactly 
similar  to  that  shown  by  Fig.  93.  This  upper  arteriole  exhibits  great 
thickening  of  the  intima,  and  if  the  section  is  examined  more  highly 
magnified  it  is  seen  that  the  tissue  of  the  intima  contains  many  of 
the  same  hollowed  cells  visible  in  the  intima  of  the  vessel  shown  by 
Fig.  93.  The  muscularis,  which  requires  higher  amplification  to 
distinguish  very  clearly,  is  in  close  contact  with  the  surrounding  fibrous 
tissue,  and  there  is  no  trace  of  any  separation  of  the  adventitia  of  the 
vessel  from  the  tissue  of  the  trabecula  in  which  it  lies.  The  appearance 
exhibited  by  this  vessel  (Fig.  94)  and  by  Fig.  93  is  exceedingly  common 
in  the  spleen.  This  condition  of  the  blood-vessels  is  frequently  found 
in  the  bodies  of  persons  dead  of  almost  every  kind  of  disease,  and  it 
is  especially  apt  to  be  found  in  those  who  have  died  of  Bright's  disease 
— which  both  of  these  patients  had,  although  in  the  case  of  the  man 
from  whom  Fig.  94  was  obtained  the  kidney  disease  was  apparently 
an  incident  in  the  course  and  progress  of  the  myelitis  from  which  he 
died.  However,  it  would  be  difficult  to  prove  whether  the  myelitis 
or  the  contraction  of  the  kidney  started  first,  for  the  symptoms  of 
disease  of  the  spine  manifested  themselves,  but  there  never  were  any 
symptoms  of  the  disease  of  the  kidney. 

In  conclusion,  it  may  be  said  that  it  might  have  been  expected  that 
the  study  of  the  blood-vessels  of  the  spleen  would  prove  inconclusive, 
since  the  function  of  the  organ  remains  unknown  and  there  is  still 
much  to  be  learned  of  its  anatomy.  It  is  something,  however,  to 
know  that  its  arteries  are  prone  to  be  affected  by  endarteritis  of  the 
same  character  as  that  which  attacks  those  of  other  organs  and  tissues, 
and  that  this  disease  of  the  intima  of  the  arteries  of  the  spleen  occurs 
at  almost  all  periods  of  life  and  in  persons  dead  of  almost  every  disease. 


CHAPTER     XII 
THE  BLOOD-VESSELS  OF  THE  KIDNEY 

THE  blood-vessels  of  the  kidney  have  probably  been  more  exten- 
sively studied  than  those  of  any  other  organ.  I  have  myself  ex- 
amined a  greater  number  of  them  than  of  any  others  except  those  of 
the  heart,  of  which  I  have  made  a  special  study.  Although  this  is 
the  case,  I  have  less  to  say  about  the  kidney  than  has  been  said  of  the 
other  organs,  both  because  the  anatomy  of  the  blood-vessels  of  the 
kidney  is  better  known  and  because  a  good  many  drawings  of  blood- 
vessels of  the  kidneys  have  been  included  in  other  chapters  of  this  work, 
as  they  illustrated  points  connected  with  the  subjects  of  those  chapters. 
The  general  anatomy  of  the  kidney  is  better  understood  than  that  of 
most  organs,  and  there  is  no  good  reason  to  suppose  that  very  much 
remains  to  be  discovered  in  regard  to  the  circulation  of  the  blood  in 
the  kidney.  Its  flow  has  been  thoroughly  traced  from  its  entrance  by 
the  renal  arteries  to  its  departure  by  the  veins.  The  ramifications  of 
the  capillaries  among  the  tubules  and  the  entrance  of  the  afferent 
and  the  exit  of  the  efferent  vessels  of  the  Malpighian  tufts  and  the 
convolutions  of  the  intervening  capillary  loops  have  been  seen  in 
every  stage  of  their  course.  Although  the  circulation  seems  in  some 
respects  to  be  complicated,  it  is  arranged  upon  a  very  simple  plan. 
Two  statements  may  be  made  with  regard  to  the  kidney :  first,  no 
text-book  contains  an  accurate  description  or  illustrations  of  perfectly 
normal  renal  blood-vessels,  any  more  than  of  the  blood-vessels  of  the 
other  organs,  and  therefore  any  one  who  studies  disease  of  the  kidney 
is  constantly  confronted  with  the  difficulty  of  deciding  whether  a 
particular  blood-vessel  is  normal  or  diseased ;  and,  second,  the  blood- 
vessels of  no  other  organ  are  so  prone  to  be  affected  by  endarteritis 
as  those  of  the  kidney,  unless  the  disease  is  even  more  common  in 
the  heart.  The  very  commonest  morbid  appearance  of  kidney 
which  has  undergone  fibroid  or  almost  any  other  form  of  chronic 
degeneration  is  that  the  blood-vessels,  and  especially  the  arterioles, 
are  thickened  inwards.  Frequently  this  thickening  of  the  intima  is  so 
great  that  the  affected  vessels  are  nearly  closed.  The  appearance  of 


THE  BLOOD-VESSELS  OF  THE  KIDNEY 


121 


a  blood-vessel  diseased  in  this  manner  is  entirely  different  from  that 
of  a  normal  vessel.  The  normal  vessels  in  cross-sections  are  seen 
to  be  thin-walled,  with  relatively  large  lumina,  while  those  which  are 
diseased  are  thick-walled  and  the  openings  are  small — often  so  small 
as  to  be  insignificant.  Whether  disease  of  the  blood-vessels  of  the 
kidney  attacks  them  early,  and  stands  in  a  causative  relation  to  the 
other  lesions  which  generally  accompany  it,  or  is  only  an  effect,  has 
not  yet  been  discovered.  It  is  perfectly  well  known  by  anatomists, 
but  is  not  so  generally  known  as  it  should  be,  that  the  kidney  of  the 
adult  man  is  supplied  with  blood  not  by  the  renal  arteries  alone,  but 
also  by  small  arterioles  which  pass  through  the  capsule  of  the  kidney 
and  enter  the  organ  from  the  outer  curved  surface. 

Fig.  95  is  a  cross-section  of  an  artery  extending  from  the  perirenal 
fat  through  the  capsule  into  the  kidney  of  a  man  seventy  years  old 
who  died  of  chronic  myelitis.  It  is  a  fully  developed  artery  like  any 
other,  it  has  three  coats, — adventitia,  muscularis,  and  intima, — and 
the  plicated  membrane  is  easy  to  see.  This  artery,  however,  as  were 
many  of  the  other  arteries  of  the  same  kidney,  is  diseased.  The  ad- 
ventitia is  normal ;  the  muscularis  is  unevenly  thick,  but  this  is  not  of 
great  degree  ;  the  intima  is  very  much  thicker  than  is  normal  and  it  is 
unevenly  thick.  A  curious  and  unusual  feature  is  the  situation  of  the 
plicated  membrane,  which,  instead  of  forming  the  boundary  between 
the  muscularis  and  intima,  as  it  ordinarily  does,  is  in  places  directly  in 
the  middle  of  the  intima.  This  is  a  condition  that  I  have  not  seen 
before,  although  I  have  examined  a  great  many  arteries.  Ordinarily 
the  plicated  membrane  is  directly  in  contact  with  the  muscularis  around 
its  entire  circuit,  and  this  situation  of  the  plicated  membrane  renders 
it  easy  to  distinguish  to  which  of  the  coats  disease  belongs.  The 
nearest  approach  that  I  have  seen  to  a  condition  like  this  is  exhibited 
by  Fig.  10,  "  Origin  of  Disease."  The  plicated  membrane  of  the  artery 
represented  by  that  drawing  is  split  in  two,  and  one  of  the  split  ends 
extends  into  the  intima  instead  of  lying  between  the  muscularis  and 
the  intima.  Both  the  thickening  of  the  intima  and  the  unusual 
situation  of  the  plicated  membrane  in  the  middle  of  the  intima  shown 
by  Fig.  95  must  be  the  results  of  disease.  At  present  the  record  of 
such  facts  as  these  seems  almost  useless,  for  it  is  impossible  now  to 
know  what  the  disease  means,  what  causes  it,  or  if  it  has  any  con- 
sequences which  are  of  importance.  The  record  appears  especially 


122  HUMAN  BLOOD-VESSELS 

useless,  perhaps,  because  the  artery  is  one  of  those  which  pass  through 
the  capsule  of  the  kidney  to  enter  the  organ  from  its  outer  curved 
surface.  Little  attention  has  been  paid  to  this  system  of  blood- 
vessels by  anatomists,  and  as  yet  none  at  all  has  been  paid  to  their 
diseases.  Recently  an  operation  has  been  advocated  for  the  removal 
of  the  capsules  of  fibroid  kidneys,  and  it  has  been  claimed  that  it"  aids 
to  establish  a  collateral  circulation  and  thus  to  cure  cases  of  con- 
tracted kidney.  In  my  book  on  the  "Origin  of  Disease"  one  of 
these  arteries  distributed  to  the  surface  of  the  kidney  is  depicted 
by  Fig.  107,  and  at  page  132  I  described  its  peculiarities,  and  men- 
tioned the  fact  that  it  is  almost  certain  that  these  arteries  are  not 
developed  in  the  embryo,  but  are  a  post-embryonic  growth.  The 
general  question,  to  what  extent  development  continues  after  birth 
in  the  higher  animals,  and  the  particular  one,  at  what  time  the 
vascular  supply  to  the  surface  of  the  kidney  is  formed,  are  inter- 
esting and  very  likely  of  importance,  but  at  present  they  are  both 
quite  unanswerable. 

Fig.  96  shows  a  diseased  blood-vessel  and  Malpighian  bodies  of 
the  contracted  kidney  of  a  woman  forty-two  years  old  who  died  of 
cerebral  apoplexy.  Most  of  the  results  of  fibrosis  and  contraction 
of  the  kidney  are  well  known  and  many  of  the  effects  are  depicted  in 
text-books,  for  this  subject  has  been  most  extensively  studied.  The 
drawing  is  therefore  intended  only  to  emphasize  what  is  already 
known.  There  are  three  Malpighian  bodies  which  are  so  changed 
by  disease  that  from  their  appearance  alone  it  would  be  quite  impos- 
sible to  recognize  them.  They  are  masses  of  fibroid  tissue  with 
nuclei,  and  in  one  of  them  two  capillaries  can  still  be  distinguished. 
The  blood-vessel  is  probably  a  diseased  arteriole.  It  is  a  mass  of 
fibroid  material  containing  nuclei,  and  there  is  a  small  eccentrically 
placed  opening  which  is  the  lumen.  Around  the  Malpighian  bodies 
and  diseased  blood-vessel  which  lie  in  a  degenerated  fibrous  portion  of 
the  kidney,  are  scattered  kidney  tubules  which  were  cut  in  various 
directions.  Fig.  96  affords  a  striking  illustration  of  what  happens  to 
the  smaller  blood-vessels  of  contracted  kidneys.  Not  only  has  the 
small  arteriole  been  converted  by  the  disease  almost  entirely  into 
fibrous  tissue,  but  the  Malpighian  tufts,  which  when  normal  are  com- 
posed of  little  else  but  capillaries,  are  turned  into  dense  balls  of  fibrous 
tissue,  hardly  a  trace  of  the  capillaries  remaining. 


FIG.  95. — ARTERY  EXTENDING  FROM  PERINEAL  FAT  INTO  KIDNEY.     (X  50.) 

From  a  man  seventy  years  old  who  died  of  chronic  myelitis.  It  is  a  fully  developed  ar- 
tery, having  three  coats  and  a  distinct  plicated  membrane.  Like  most  blood-vessels  of  old 
people  it  is  not  like  the  standards  of  the  normal,  for  the  intima  is  thicker  than  is  considered 
to  be  natural  in  so  small  an  artery,  and  the  plicated  membrane  is  in  places  in  the  middle  of 
the  intima  instead  of  forming  the  boundary  between  the  intima  and  muscularis,  as  is  usual. 
This  latter  is  an  unusual  feature  and  is  difficult  to  explain. 


FIG.  95. 


FIG.  96.— DISEASED   BLOOD-VESSELS  OF  FIBROID  KIDNEY.     (X  105.) 

From  a  woman  forty-two  years  old  who  died  of  cerebral  apoplexy.  The  section  is  from 
the  cortical  portion  of  a  very  contracted  kidney,  g,  g,  two  Malpighian  bodies  which  have 
undergone  fibroid  contraction  to  such  an  extent  that  no  trace  of  the  capillaries  can  be  dis- 
tinguished ;  d,  a  fibroid  Malpighian  body  in  which  the  openings  of  two  capillaries  can  be 
seen ;  z/,  a  blood-vessel.  It  is  probably  an  arteriole  in  which  the  intima  was  thickened  to 
such  an  extent  as  to  produce  the  effect  that  is  seen.  The  lumen  is  very  small ;  it  is  not  cen- 
trally placed,  and  the  wall  of  the  vessel  has  lost  all  of  the  ordinary  cellular  structure  and 
differentiation  of  three  coats.  Such  changes  are  very  common  in  arterioles  of  this  size. 


FIG.  96. 


•m*$mti^s& 


THE  BLOOD-VESSELS  OF  THE  KIDNEY  123 

My  discussion  of  the  subject  of  the  blood-vessels  of  the  kidneys  is 
very  incomplete  and  perhaps  unsatisfactory,  but  so  much  has  been 
written  of  it  by  others,  and  I  have  already  recorded  so  much  regarding 
it  in  the  chapters  on  the  kidney  and  on  the  blood-vessels  in  my  book 
on  the  "  Origin  of  Disease  "  and  in  various  of  the  other  chapters  of 
this  work,  that  it  has  not  seemed  to  me  to  be  desirable  to  include 
more  here  than  the  brief  record  I  have  made,  and  to  reiterate,  in  con- 
clusion, that  the  studies  of  the  blood-vessels  of  the  kidney  and  of  the 
heart  have  been  more  thorough  and  the  results  more  satisfactory  than 
can  be  said  to  be  the  case  concerning  those  of  any  of  the  other  organs 
or  tissues. 


CHAPTER   XIII 
THE  BLOOD-VESSELS  OF  THE  BRAIN  AND  SPINAL  CORD 

THE  blood-vessels  of  the  brain  and  spinal  cord  and  their  diseases 
have  already  been  discussed  and  drawings  of  them  have  been  included 
in  Chapters  I  and  IV.  It  is  undesirable  to  repeat  to  any  extent 
what  has  already  been  said,  and  yet  a  certain  amount  of  repetition 
may  be  unavoidable.  Most  of  the  blood-vessels  of  the  brain  and 
spinal  cord,  and  all  of  the  largest  ones,  are  situated  in  the  mem- 
branes outside  the  actual  nerve-tissue,  for  only  small  vessels  penetrate 
the  nerve  substance  itself.  The  greater  number  of  the  vessels  and  all 
of  the  large  ones  are  suspended  in  the  loose  tissue  of  the  meninges, 
and  are  therefore  without  any  external  support  like  that  which  is 
afforded  by  surrounding  tissue  to  those  within  the  substance  of  the 
liver,  kidney,  and  heart,  and  even  of  the  lung,  although  the  latter 
organ  is  of  a  light  and  spongy  consistency.  In  this  respect  the  large 
vessels  of  the  nervous  system  resemble  the  main  arterial  and  venous 
trunks,  which  are  generally  situated  in  the  cavities  and  spaces  of  the 
body  in  such  a  manner  that  they  also  are  suspended  by  the  perivas- 
cular  connective  tissue,  and  are  without  support  from  any  surrounding 
solid  tissue.  It  seems  to  me  that  the  blood-vessels  of  the  brain  and 
of  the  spinal  cord  are  less  frequently  affected  by  endarteritis  than  the 
vessels  of  many  other  parts,  especially  those  of  the  thoracic  and  abdom- 
inal viscera  and  the  large  arterial  trunks  such  as  the  radial  and  femoral 
and  even  the  aorta.  In  my  experience  it  has  been  comparatively 
rare  to  find  blood-vessels  of  the  nervous  system  with  thick  walls  and 
small  calibres  like  those,  for  instance,  which  are  so  common  in  the 
kidney  and  in  the  heart.  Cerebral  hemorrhage  is  one  of  the  most 
frequent  causes  of  death  in  persons  past  fifty  years  of  age.  It  may  be 
that  part  of  the  reason  for  this  is  because  the  arteries  of  the  brain  are 
less  liable  to  thickening  of  their  walls  than  those  of  other  tissues.  In 
my  book  on  the  "Origin  of  Disease,"  at  page  172,  I  expressed  the 
opinion  that  cerebral  hemorrhage  is  due  to  ulceration  of  the  lining  of 
the  arteries,  which  produces  gradual  thinning  of  the  walls,  until  finally 
rupture  takes  place  as  a  result  of  the  ulceration,  and  that  strain  and 
124 


BLOOD-VESSELS  OF  THE  BRAIN  AND  SPINAL  CORD     125 

violence  generally  do  not  have  any  influence  in  precipitating  the 
rupture  and  hemorrhage.  If  this  be  true,  the  process  is  exactly  similar 
to  what  occurs  in  perforation  of  the  intestine  in  typhoid  fever.  It 
may  be  that  if  the  thickening  of  the  blood-vessels  which  occurs  with 
advancing  years  is  a  partially  conservative  process,  and  if  the  vessels 
of  the  nervous  system  were  more  subject  to  it,  death  from  cerebral 
hemorrhage  would  be  less  frequent. 

Fig.  97  is  an  illustration  of  an  artery  and  a  venous  capillary  from 
the  brain  of  a  girl  eighteen  years  old  who  died  of  typhoid  fever. 
They  are  from  the  surface  of  the  cerebrum,  and  it  is  fair  to  assume 
that  they  are  natural.  The  artery  occupies  the  centre  in  the  draw- 
ing, and  it  is  filled  with  blood -corpuscles ;  its  wall  is  normal.  The 
venous  capillary  is  above  the  artery,  and  the  curious  feature  shown 
by  the  drawing  is  that  the  accompanying  return  vessel  of  an  artery 
of  such  considerable  size  may  sometimes  be  a  capillary  in  structure 
instead  of  being  a  vein.  The  wall  of  the  vessel  is  formed  of  a  very 
thin  layer  of  fibrous  tissue  which  contains  nuclei.  There  is  nothing 
resembling  a  division  into  three  coats,  nor  is  there  a  trace  of  muscular 
tissue  in  the  wall  of  the  vessel.  This  fact,  that  the  accompanying 
return  vessels  found  with  arteries  sometimes  are  capillaries,  is  well 
known  to  anatomists,  but  it  is  not  so  generally  known  as  it  should  be. 
The  subject  is  discussed  in  Chapter  I,  and  Fig.  18  represents  a  pair 
of  the  vessels  from  the  spinal  cord. 

Figs.  98  and  99  depict  an  artery  and  a  venous  capillary  from  the 
spinal  cord  of  a  woman  twenty-six  years  old  who  died  of  typhoid 
fever.  The  artery  is  natural,  and  the  venous  capillary  exhibits  much 
the  same  character  as  Fig.  97.  The  wall  of  this  capillary  is  formed 
of  fibrous  tissue  and  there  is  nothing  like  the  division  into  three  coats 
which  is  characteristic  of  normal  veins.  As  these  two  vessels  are  a 
good  deal  larger  than  those  represented  by  Fig.  97,  their  walls  are 
naturally  much  thicker.  This  anatomical  arrangement,  where  the 
capillaries  which  perform  the  function  of  returning  the  blood  to  the 
heart  are  of  so  much  greater  size  than  any  of  the  ordinary  capillaries 
which  are  occupied  in  the  work  of  supplying  blood  to  the  tissues,  is 
a  curious  one,  and  it  will  very  probably  some  day  be  discovered  to 
have  an  important  influence  in  the  production  of  disease  or  in  deter- 
mining its  course.  In  Chapter  VIII  the  large  capillaries  that  exist  in 
the  heart  are  described  and  they  are  represented  by  drawings. 


126  HUMAN  BLOOD-VESSELS 

Fig.  100  shows  a  blood-vessel  of  the  spinal  cord  of  a  woman  of 
twenty-six  years  who  died  of  typhoid  fever.  It  is  not  one  of  the 
vessels  of  the  meninges,  but  lay  within  the  spinal  cord.  This  is  shown 
by  the  drawing,  for  the  nerves  are  cut  across  and  lie  adjacent  to  the 
vessel  upon  either  side  of  it.  The  appearance  of  the  vessel  is  one 
which  is  not  rare  in  the  brain  and  spinal  cord,  but  it  is  one  I  am  quite 
unable  to  explain,  nor  can  I  even  say  whether  it  is  natural  or  is  due 
to  disease.  There  are  many  blood-corpuscles  lying  in  the  lumen  of  the 
vessel.  The  walls  are  not  like  those  of  any  of  the  normal  blood-vessels. 
They  are  composed  of  an  outer  and  an  inner  layer  of  dense  fibrous 
tissue,  between  which  is  tissue  that  is  also  fibrous  but  is  much  less 
dense.  The  lines  of  the  fibres  in  this  vessel  all  run  longitudinally.  The 
blood-vessel  cannot  be  classified  as  an  artery  nor  as  a  vein,  and  if  it  be  a 
capillary  it  is  not  like  any  of  the  normal  ones  as  they  are  ordinarily 
described.  It  is  possible  that  the  condition  depicted  may  be  the  result 
of  typhoid  fever,  of  which  disease  the  patient  died.  In  typhoid  fever  the 
tissues  are  often  very  much  softened,  and  the  walls  of  the  vessel  might 
have  become  swollen  owing  to  exudation  of  the  nature  of  oedema. 

Fig.  101  shows  an  artery  of  the  circle  of  Willis  at  the  base  of  the 
brain  of  a  negro  man  seventy-four  years  old  who  died  of  hemiplegia. 
The  artery  is  very  much  degenerated.  The  adventitia  and  muscularis 
are  readily  distinguished,  and  it  is  easy  to  see  that  both  are  thinner 
than  is  usual  in  arteries  of  their  size.  The  reason  for  this  is  not  evi- 
dent. All  the  tissue  that  lies  inside  of  the  muscularis  is  intima,  and 
it  is  very  much  thickened  and  degenerated.  Greater  amplification 
than  was  used  shows  more  of  the  details  of  structure  and  of  the  degen- 
eration, but  a  great  deal  is  shown  by  the  drawing.  There  are  many 
cavities  in  the  tissue,  and  a  glance  reveals  that  it  is  almost  disinte- 
grated, for  it  is  quite  unlike  the  well-organized  tissue  which  forms  the 
intima  in  most  thickened  arteries.  It  was  said  in  the  earlier  part  of 
this  chapter  that  endarteritis  is  less  common  in  the  brain  and  spinal 
cord  than  in  some  of  the  other  tissues.  The  appearance  of  this  vessel 
shows  that  the  condition  does  occur  even  if  it  is  not  so  common. 
However,  much  as  the  arterial  wall  is  thickened,  it  is  but  little  so  in 
comparison  with  what  occurs  in  the  arteries  of  other  parts.  The  state 
of  disease  exhibited  by  this  artery  is  interesting  as  showing  what  may 
be  found  in  the  large  arteries  of  the  base  of  the  brain  of  an  old  man 
dead  of  hemiplegia. 


FIG.  97. — NORMAL  ARTERY  AND  VENOUS  CAPILLARY  OF  THE  BRAIN.     (X  105.) 

From  the  cerebrum  of  a  girl  eighteen  years  old  who  died  of  typhoid  fever.  The  artery 
is  below  and  its  lumen  is  filled  with  blood-corpuscles.  The  venous  capillary,  which  is 
directly  above  the  artery,  has  the  character  of  ordinary  capillaries.  Its  wall  is  a  fine  thread 
of  endothelium  containing  nuclei.  The  striking  feature  is  that  the  accompanying  venous 
vessel  of  such  a  good-sized  artery  should  be  a  capillary. 

FIG.  98. — ARTERY  OF  THE  SPINAL  CORD.     (X  50.) 
From  a  woman  twenty-six  years  old  who  died  of  typhoid  fever.    It  appears  to  be  normal. 

FIG.  99. — VEIN  OF  THE  SPINAL  CORD.     (X  50.) 

From  the  same  case  as  Fig.  98.  It  is  probably  normal.  The  noticeable  feature  is  that 
the  wall  of  the  vein  is  simply  a  ring  of  fibrous  tissue,  there  being  no  division  into  adventitia, 
muscularis,  and  intima,  as  the  ordinary  histological  descriptions  portray  veins  of  its  size. 


FIG.  97. 


FIG. 


FIG.  99. 


FIG.   100. — BLOOD-VESSEL  OF  THE  SPINAL  CORD.     (X  240.) 

From  a  woman  of  twenty-six  years  who  died  of  typhoid  fever.  There  are  many  blood- 
corpuscles  lying  within  the  lumen  of  the  vessel,  and  outside  of  it  are  seen  the  nerve-fibres  of 
the  cord.  The  vessel  wall  is  composed  of  an  inner  and  an  outer  line  of  fibrous  material  with 
a  layer  of  lighter  tissue  between  them.  There  is  no  muscularis  or  intima. 

FIG.  101. — DISEASED  ARTERY  FROM  THE  CIRCLE  OF  WILLIS.     (X2O. ) 

From  a  negro  man  seventy-four  years  old  who  died  of  hemiplegia.  a,  adventitia  ;  ///,  mus- 
cularis ;  f,  a  clot  lying  within  the  lumen  of  the  artery.  The  adventitia  and  muscularis  com- 
pose a  small  part  of  the  total  thickness  of  the  vessel  wall.  All  of  the  tissue  lying  within  the 
muscularis  is  the  intima,  which  is  disintegrated  and  full  of  cavities  produced  by  disease. 
Examined  with  higher  power  it  can  be  seen  that  much  of  the  tissue  of  the  intima  is  structure- 
less owing  to  the  extensive  disintegration. 


i^ 


FIG.   100. 


^ 


FIG.   101. 


BLOOD-VESSELS  OF  THE  BRAIN  AND  SPINAL  CORD     127 

Fig.  102  gives  a  representation  of  the  basilar  artery  and  a  small 
arteriole  of  a  man  thirty  years  old  who  died  of  hemiplegia,  the  cause 
of  which  was  thought  to  be  syphilis,  but  this  diagnosis  could  not  with 
certainty  be  established.  A  number  of  curious  things  are  shown 
by  the  drawing.  The  basilar  artery  is  entirely  filled  by  a  clot  which 
was  easily  seen  with  the  unaided  eye  before  the  vessel  was  cut  and 
prepared  for  microscopical  examination.  At  page  1 2  it  is  stated  that 
during  life  the  plicated  membrane  is  straight  and  that  its  folds  are 
the  result  of  post-mortem  shrinkage,  and  there  are  illustrations  to 
show  how  differently  it  appears  in  different  sections  of  the  same 
artery  if  some  pieces  are  allowed  to  shrink  unobstructed  in  the  course 
of  preparation  for  microscopical  examination  and  others  are  prepared 
with  rigid  glass  rods  in  their  calibres  to  prevent  shrinkage.  This  dis- 
eased basilar  artery,  which  is  filled  with  an  organized  clot,  demon- 
strates the  correctness  of  the  opinion  that  the  folds  of  the  plicated 
membrane  are  due  to  post-mortem  shrinkage.  The  clot  is  so  large 
and  so  firm  that  it  has  done  exactly  what  the  glass  rods  did  in  the 
vessels  in  which  they  were  placed  in  the  experiments  to  which  allusion 
has  been  made, — post-mortem  shrinkage  was  to  a  great  extent  pre- 
vented, because  the  calibre  of  the  artery  was  filled  by  the  clot.  To 
the  left  in  the  drawing  the  plicated  membrane  is  easily  seen,  although 
to  the  right  it  cannot  be  distinguished  at  all,  as  it  has  been  destroyed 
by  the  disease.  No  part  of  the  plicated  membrane  that  remains  is 
folded  as  much  as  it  usually  is  in  vessels  prepared  as  this  one  was,  but 
the  lower  portion  of  it  shows  the  corrugated  or  wavy  appearance  quite 
distinctly,  while  above  it  appears  as  a  perfectly  straight  glassy  mem- 
brane. The  straight  portion  is  exactly  like  what  is  shown  by  Fig.  1 1 .  It 
is  singular  that  disease  should  have  filled  the  lumen  of  this  artery  with 
clot  so  as  to  reproduce  almost  exactly  the  conditions  obtained  by  my 
experiments  of  preparing  pieces  of  arteries  with  glass  rods  in  them  to 
prevent  shrinkage.  An  interesting  process  shown  by  this  artery  is 
organization  of  clot  and  its  relation  to  the  tissue  of  the  arterial  wall. 
To  the  left  the  adventitia,  the  muscularis,  and  the  plicated  membrane 
are  perfectly  distinct  and  are  easy  seen,  but  at  other  parts  of  the  large 
irregular  circle  or  oval  formed  by  the  vessel  they  cannot  be  dis- 
tinguished. If  the  muscularis  upon  the  left  is  followed  upward  with  the 
eye,  it  is  seen  to  form  an  angle  which  must  have  been  caused  by 
shrinkage,  and  a  little  beyond  this  point  as  it  passes  toward  the  right 


i28  HUMAN  BLOOD-VESSELS 

it  widens  somewhat  and  then  disappears  into  a  mass  of  diseased 
tissue.  In  this  region  it  is  impossible  to  recognize  any  difference  be- 
tween the  tissue  which  forms  the  arterial  wall  and  the  clot  which  fills 
the  lumen  of  the  vessel.  This  is  distinctly  shown  by  the  drawing,  but 
if  the  section  be  examined  under  greater  amplification  still  more  de- 
tails of  the  structure  can  be  recognized.  The  manner  in  which  the 
vessel  wall  and  the  clot  merge  together  is  surprising.  At  the  central 
portion  the  clot  is  yellowish  and  it  is  formed  of  partially  disorganized 
blood,  at  the  periphery  the  tissue  of  the  arterial  wall  is  distinct,  but 
between  these  two  extremes  a  great  part  of  the  material  is  of  such  a 
nature  that  it  is  impossible  to  say  whether  it  is  arterial  wall  or  clot, 
and  it  is  quite  impossible  to  draw  a  line  showing  where  natural  tissue 
ends  and  clot  begins.  The  condition  of  disease  exhibited  and  that 
of  organization  of  clot  are  sufficiently  common,  but  the  drawing  shows 
them  unusually  well. 

Fig.  103  shows  the  small  arteriole  b  in  Fig.  102.  The  disease  was, 
as  has  already  been  said,  probably  syphilis.  It  is  perfectly  evident 
that  the  vessel  is  not  normal,  but  the  only  abnormality  that  can  be  dis- 
tinguished is  infiltration.  The  muscularis  is  easily  recognized,  and  at 
its  upper  portion  there  is  a  thick  layer  of  infiltrated  tissue  inside  of  it ; 
at  the  lower  portion  there  is  a  large  area  of  infiltration,  but  this  lies 
outside  of  the  muscularis,  and  it  looks  therefore  as  if  the  infiltration 
had  had  its  origin  in  the  adventitia  or  entirely  outside  of  the  blood- 
vessel, in  the  perivascular  tissue.  Syphilitic  and  tubercular  disease 
of  arteries  have  been  described,  and  it  has  been  thought  by  some  that 
they  could  be  recognized  by  their  appearance  without  regard  to  the 
clinical  history  of  the  patient  or  to  other  lesions.  There  cannot  be 
any  doubt  that  inflammation  also  is  capable  of  producing  arterial 
disease.  It  is  my  belief  that  syphilis,  tuberculosis,  and  inflammation 
produce  effects  upon  the  arteries  which  in  their  microscopical  ap- 
pearances are  identical.  These  diseases  are  therefore  indistinguish- 
able unless  the  clinical  history  of  the  patient  or  something  in  the 
gross  appearance  of  the  lesions  tells  which  of  the  three  is  present. 
The  lesion  which  is  common  to  the  three  diseases  is  cell  infiltration. 
This  effect  is  characteristically  shown  by  Fig.  103,  which  depicts  an 
arteriole  of  a  man  thirty  years  old  who  died  of  hemiplegia.  The 
hemiplegia  was,  of  course,  not  due  to  the  clot  in  the  basilar  artery, 
and  there  is  no  positive  proof  that  the  disease  was  syphilitic  ;  but  the 


FIG.  102. — DISEASED  BASILAR  ARTERY  OCCLUDED  BY  CLOT.      (X  20.) 

From  a  man  thirty  years  old  who  died  of  hemiplegia  (probably  syphilitic).  i>,  a  blood- 
vessel represented  more  highly  magnified  by  Fig.  103.  »/,  muscularis,  which  towards  the 
other  side  of  the  artery  becomes  indistinguishable,  for  it  merges  into  the  diseased  tissue  and  the 
clot.  /,  plicated  membrane.  Parts  of  it  are  folded,  as  usual,  and  other  parts  are  straight, 
owing  to  the  fact  that  the  lumen  of  the  artery  is  filled  with  clot  which  distends  it  and  pre- 
vented the  usual  post-mortem  shrinkage,  e  is  a  region  where  the  wall  of  the  artery  and  the 
clot  come  together  and  have  commingled  so  that  it  is  impossible  to  distinguish  where  the  clot 
ends  and  the  tissue  begins.  It  is  a  good  exemplification  of  the  organization  of  clot. 

FIG.  103. — INFLAMMATION  OF  A  BLOOD-VESSEL.     (X  50.) 

Enlarged  view  of  the  blood-vessel  b  in  Fig.  102.  The  case  was  probably  one  of  syphilis. 
The  appearance  is  identical  with  the  disease  commonly  described  as  tubercular  arteritis.  m 
is  the  muscular  coat  and  it  can  be  distinguished  all  the  way  around  the  vessel.  At  the  top  it 
is  most  distinct,  and  below  it  is  obscured  by  the  cellular  infiltration  which  has  resulted  from 
the  process  of  inflammation. 


FIG.  102. 


FIG.   103. 


BLOOD-VESSELS  OF  THE  BRAIN  AND  SPINAL  CORD     129 

clinical  evidence  seemed  to  point  that  way  and,  besides,  syphilis  is  the 
most  frequent  cause  of  hemiplegia  in  young  persons.  In  my  book  on 
the  "Origin  of  Disease,"  Fig.  33  represents  an  arteriole  from  a 
tuberculous  area  of  the  lung,  and  at  page  58  of  that  book  it  is  as- 
serted that  the  disease  which  is  shown  by  the  drawing  is  an  over- 
whelming cell  infiltration  which  looks  as  if  it  had  had  its  origin  in  an 
invasion  of  the  blood-vessel  wall  from  the  outside,  and  it  is  further  said  : 
"  tubercular  arteritis,  therefore,  has  no  real  existence,  and  the  condi- 
tion is  nothing  but  the  involvement  of  the  vessels  by  the  cellular  in- 
filtration which  is  characteristic  of  the  tubercular  process  every- 
where." The  appearance  of  the  arteriole  lying  in  the  very  midst  of 
a  tuberculous  portion  of  lung  is  identical  with  that  of  Fig.  103,  al- 
though the  diseases  were  clinically  so  different  and  the  one  arteriole 
was  from  the  lung  and  the  other  from  the  brain.  In  both  instances 
the  appearances  tend  to  make  one  think  the  disease  had  its  origin  in 
the  tissue  around  the  vessels  and  included  them  in  the  course  of  its 
progress  rather  than  that  it  was  really  of  vascular  origin.  It  is  a 
matter  of  common  knowledge  to  those  who  have  studied  pathological 
histology,  that  in  any  tissue  which  is  subjected  to  the  process  of  in- 
flammation, as  cellular  infiltration  increases  and  takes  in  more  terri- 
tory in  the  course  of  its  progress,  the  blood-vessels  of  the  invaded 
tissue  are  infiltrated  by  the  cells  just  as  all  of  the  rest  of  the  tissue  is, 
and  that  this  infiltration  attacks  first  the  adventitia  and  then  proceeds 
through  the  muscularis,  the  intima,  and,  finally,  if  the  inflammation  is 
sufficiently  active,  the  lumen  of  the  vessel  is  filled  by  the  cells,  and  in 
the  end  all  sign  of  the  blood-vessel  disappears,  its  place  being  taken  by 
a  mass  of  cells.  The  two  arterioles  that  have  been  described,  the  one 
from  a  tuberculous  portion  of  lung  and  the  other  from  the  brain  of  a 
man  who  died  of  hemiplegia  which  was  probably  syphilitic,  show 
that  in  the  two  dissimilar  diseases  similar  lesions  resulted.  It  can- 
not be  doubted  that  inflammation  can  produce  the  same  disease  of 
blood-vessels,  and  therefore  it  is  no  more  than  just  to  say  that  the 
three  conditions  of  disease — tuberculosis,  syphilis,  and  inflammation — 
may  produce  identical  histological  changes  of  the  blood-vessels. 

In  conclusion,  it  seems  best  to  repeat  that  a  great  deal  that  has 

been  included  in  this  book  is  of  an  unsatisfactory  nature  and  does  not 

lead  to  any  definite  result.     This  has  been  unavoidable,  for  the  reason 

that  many  of  the  illustrations — and  it  is  upon  the  illustrations  to  a 

9 


i3o  HUMAN  BLOOD-VESSELS 

large  extent  that  the  book  is  founded — are  of  conditions  that  I  am 
quite  unable  to  explain.  Such  illustrations  were  included,  however, 
in  the  hope  that  the  day  may  come  when  their  peculiarities  will  be 
explained  and  that  they  may  then  be  of  value.  The  subject  of  the 
microscopical  anatomy  of  the  blood-vessels  has  not  yet  been  suffi- 
ciently studied  to  make  the  record  of  it  satisfactory  and  the  pathology 
of  the  blood-vessels  is  but  little  understood.  If  my  record  adds  any- 
thing to  the  knowledge  of  the  anatomy  of  the  blood-vessels  or  of 
their  diseases,  it  will  have  fulfilled  the  purpose  for  which  I  made  it. 


INDEX 


Abortive  new  blood-vessels,  29,  33 
Acute  and  chronic  disease  of  lungs,  94 
inflammation  of  blood-vessels, 

7i 
Adventitia,  118 

disease  of,  38 

of  arteries,  disease  of,  68 

of  artery  of  lung,  100,  102 

of  blood-vessels    and    perivascular 
tissue,  6 

of  veins,  disease  of,  51,  53,  59 
Age  alters  the  blood-vessels,  3,  5,  45 

disease  of,  31,  45 

in  youth,  65 

Aneurism  of  subclavian  artery,  42 
Aorta,  10,  70 
Apoplexy,  48,  124 
Arteries  and  veins,  5 

and  veins  widely  different,  62 

atheroma  of,  47 

calcareous  disease  of,  42 

commonly  have  no  endothelial  lin- 
ing, 5 

disease  of,  37 

like  veins,  73 

new  blood-vessels  in  intima  of,  24 

of    meninges,    less    diseased    than 
veins,  71,  72 

the  coats  of,  6,  38,  44,  53 

three  coats  of,  6,  44,  53 

very  different  from  veins,  5 
Arteriole  and  venule  of  ileum,  70 
Afterioles  accompanied  by  capillaries, 

i,  15 

Arteritis,  47 
Artery  and  vein  of  kidney,  disease  of, 

,       52 

Atheroma,  47 
Atheromatous  aorta,  70 


B 

Basilar  artery,  127 

Basket-ware  appearance  of  muscularis, 

12,  13 

Billroth  and  Rindfleisch,  23 
Blood   always    confined    within    vessel 

walls,  21 
disappears     from     arteries     with 

death,  6 

supply  of  kidney,  121 
unconfined  by  vessel  walls,  114 
Blood-vessels,  calcareous  disease  of,  42 
change  with  years,  3,  5 
disease  of,  in  general,  37 
embryological  development  of,  23, 

28 
glass  rods  to  prevent  shrinkage,  7, 

10,  127 

information  regarding  them  incom- 
plete, 3 
in  inflammation  in  tuberculosis  and 

in  syphilis,  69 

in  syphilis  nearly  normal,  74 
in  tubercular  tissue,  34,  35 
living,  different  from  dead,  6,  13 
new,  23 

new,  in  lung,  101 
normal,    there    is    no    established 

standard,  4 

of  brain  and  spinal  cord,  124 
of  heart,  77 

of  heart,  injected,  83,  89 
of  heart  of  children,  86 
of  heart,   summary   of  description 

of,  87 

of  kidney,  120 
of  liver,   107 
of  lungs,  90 
of  lungs,  injected,  90 
of  lungs,  summary  of  description 
of,  104 


132 


INDEX 


Blood-vessels  of  meninges,  71 
of  spleen,  113 
of  spleen  injected,  115 
of  spleen,  ordinary  appearance  of, 

116 

shrink  at  death  and  afterwards,  6 
the  coats  of,  6,  38,  44,  53 
with  tissue  like  epithelium  in  lung, 

103 
Brain  and  spinal  cord,  blood-vessels  of, 

124 

syphilis,  blood-vessels  in,  74 
Bronchiole,   injected   blood-vessels   of, 

90 
Broncho-pneumonia,    blood-vessels    in, 

IOO 


Calcareous  disease  of  arteries,  42 
Cancer,    resemblance     to     fibrosis     of 

muscularis  of  veins,  51,  59 
Capillaries,    16 

are  ephemeral,  16,  19,  20 

disease  of,  22,  37 

injected,  19 

injected,  of  spleen,  20 

large  ones  accompany  arterioles,  2, 

rs,  77,  125 

large  ones  in  heart,  2,  77,  82 
of  bronchiole,  91 
of  heart,  77,  82 
of  lung,  91 
of  spleen,  114 
Capsule   of   spleen,   new   blood-vessels 

in,  32 
Capsules  of  organs,  new  blood-vessels 

in,  28,  30 

Cardiac  circulation,  83,  88 
Cell  characteristics  not  distinct  in  early 

embryos,  25,  56 

Central  and  peripheral  parts  of  mus- 
cular fibres  different,  80 
Cerebral  hemorrhage,  48,  124 
Chalky  deposits  in  arteries,  42 
Children,    blood-vessels    of    heart    of, 

86,  89 

Chronic  and  acute  disease  of  lungs,  94 
and  acute  inflammation  of  blood- 
vessels,   71 


Circulation  of  heart,  83,  88 

of  kidney,   120,  121 
Cirrhosis  of  liver,  109,  in 
Clot  in  basilar  artery,  127 
Clots  in  blood-vessels,  46,  63 
Coats  of  arteries,  6,  38,  43,  53 

of  veins,  51 

Compensatory  hypertrophy,  41,  55 
Conservative  effect  of  emphysema,  93 
Contracted    kidney,    blood-vessels    of, 
122 

muscle,   80 

Contraction  of  muscle,  78 
Coronary  artery  of  heart,  II 
Cross-striae  of  muscle,  83 


Dead  blood-vessels  different  from  liv- 
ing, 6 

Death,  it  is  commonly  caused  by  fail- 
ure of  lungs,  104 
Degenerative    nature    of    hypertrophy, 

41 
Development  of  new  blood-vessels,  23 

post-embryonic,   80 

Different  diseases  produce   similar  le- 
sions, 70,  76 
Diseased  arteries  and  veins  sometimes 

indistinguishable,  n,  53,  60 
capillaries  of  lung,  91 
veins  resemble  arteries,  n,  53,  60 
Disease  of  age,  31,  45,  65 
of  arteries,  37 
of  blood-vessels  arises   outside  of 

them,  75 

of  blood-vessels  in  general,  37 
of  blood-vessels  in  youth,  65 
of  capillaries,  22,  37 
of  capillaries  of  lung,  95,  98 
of  intima,  41,  44 
of  intima,  cause  of  apoplexy,  48 
of  intima,  slight  thickening  harm- 
less, 6,  14,  45 
of  muscularis,   41 
of  plicated  membrane,  44 
of  radial  arteries  and  veins,  61 
of  radial  veins  common,  65 
of  veins,  37,   50 

Diseases,  different,  produce  similar  le- 
sions, 70,  76 


INDEX 


E 

Embryological  development  of  blood- 
vessels, 23,  28 

Embryos,  tissues  alike  in,  25,  56 
Emphysema  of  the  lungs,  92 
Endarteritis,  75,  106,  109 

causes  growth  of  new  blood-ves- 
sels, 24 

in    spleen,    118,    119 
of  blood-vessels  of  brain  and  spinal 

cord,  124 

slight  degree  harmless,  6,  14,  45 
syphilitic,  38,  44 
Endophlebitis,  54,  106 
Endothelium    is    commonly    absent    in 

arteries  and  veins,  5 
Ephemeral  nature  of  capillaries,  16,  19, 

20 

Epithelium,    blood-vessels    with   tissue 
like  it  in  lung,  103 


Femoral  artery,   10 

vein,  10 

Fenestrated  membrane  of  artery  of  kid- 
ney,  121 

membrane  of  Henle,  7,  12,  42,  44, 

65,  86,  127 
Fibres  of  muscle,  79 
Fibrillae  of  muscle,  79 
Fibroid  degeneration  of  the  muscularis, 
40,  55 

disease,  31 

Fibrosis   of   blood-vessels   attacks   the 
young,  63,  65 

of  lung,  99,  101 

of  veins,   50,    51,   52,    53 
Fibrous  coat  of  vessels,  disease  of,  38 

framework  of  the  liver,  107 
Fluids,  movement  of,  the  cause  of  mus- 
cular contraction,  79 
Folding  of  plicated  membrane,  7,  12 
Framework  of  liver,  107 
Function  of  muscle,  78 


Giant  cells,  32,  35 

and  new  blood-vessels,  32 


Glass  rods  in  blood-vessels  to  prevent 

shrinkage,  7,  10,  127 
Gull  and  Sutton,  22,  39,  51,  101,  105 

H 

Heart,  blood-vessels  of,  77 

blood-vessels  of,  of  children,  86,  89 

hypertrophy  of,   40 

muscle,  structure  of,  78 

peculiarities  of  blood-vessels  of,  81 

sinus  venosus  of,  77 
Hemorrhage  of  lungs,  cause  of,  91 
Henle,  fenestrated  membrane  of,  7,  12, 
42,  44,  65,  86,   127 

membrane  of,  of  artery  of  kidney, 

121 
Hollow  cells  in  blood-vessels,  118,  119 

muscular  fibres,  80 
Hypertrophy,  degenerative,  62,  64 

of  heart,  40 

of  muscularis,  39,  41,  55 


Ileum,  arteriole  and  venule  of,  70 
Imbibition  of  fluid  the  cause  of  mus- 
cular contraction,  79 
Inflammation,    acute    and    chronic,   of 
blood-vessels,  71 

blood-vessels  in,  69 

like  tuberculosis,  72 

of  aorta,  70 

of  blood-vessels,  128 

of  plicated  membrane,  44 
Information     regarding     blood-vessels 

incomplete,  3 
Injected  blood-vessels  of  heart,  83,  89 

blood-vessels  of  lungs,  90 

blood-vessels  of  spleen,  115 

capillaries,  19 

capillaries  of  spleen,  20 
Intima,  disease  of,  41,  44 

disease  of,  in  arteries,  causes  apo- 
plexy, 48 

of  arteries,  disease  of,  68 

of  arteries,  new    blood-vessels    in, 

24 

of  arteries,  slight  thickening  harm- 
less, 6,  14,  45 


INDEX 


Intima  of  vein,  proliferation  of,  54 
thickening  of,  due  to  clot  forma- 
tion, 46 

Irregular    distribution    of     disease    of 
veins,  58,  63 

K 

Kidney,  blood  supply  of,  121 
blood-vessels  of,  120 
disease  of  artery  and  vein  of,  52 
plicated  membrane  of  artery  of,  121 

Kolliker,  80 

L 

Laennec,  92,  95 

Latent  disease,  32,  63,  87 

Leidy,  22 

Lesions    similar   in    different    diseases, 

70,  76 

Liver,  cirrhosis  of,  109,  HI 
blood-vessels  of,  107 
nutmeg,  107 
Living    blood-vessels     different     from 

dead,  6 

Lungs,  acute  and  chronic  disease  of,  94 
blood-vessels  of,  90 
disease  of  capillaries  of,  95,  98 
injected  blood-vessels  of,  90 
new  blood-vessels  in  pleura,  28,  30, 
31 

M 

Malpighian  bodies   in   contracted  kid- 
ney, 122 
McDougal,  79 
Meigs,  Edward  B.,  79 
Meninges,  blood-vessels  of,  71 
Meningitis,  new  blood-vessels  in,  28 
radial   arteries   and   veins   from   a 

case  of,  64 

Movement  of  fluids  the  cause  of  mus- 
cular contraction,  79 
Muscle,   contracted   and  uncontracted, 

80 

contraction  of,  78 
fibres,  79 
nuclei,  post-mortem  changes  of,  12, 

13 

structure  of,  78 

Muscular  fibres  of  heart  penetrated  by 
capillaries,  77,  82,  84 


Muscularis,  disease  of,  41 
hypertrophy  of,  39,  41,  55 
in  spleen,  117 
of  radial  vein,  62 
of  veins,  51,  52,  53,  54,  66,  67 
resembles  basket-ware,  12,  13 

N 

New  blood-vessels,  23,  70 

and  giant  cells,  32 

develop  in  the  young  and  old, 
23,  27 

development  of,  23,  26 

in  capsules  of  organs,   28 

in  intima  of  arteries,  24 

in  meningitis,  28 

in  pathological  growths,  24,  26 

in  vessel  walls,  24,  28 

of  liver,   no 

of  lung,  101 

of  lung  and  pleura,  28,  30,  31 

of  walls  of  hepatic  blood-ves- 
sels, 109 

sometimes  abortive,  29,  33 

with  thick  walls,  29 
Normal   blood-vessels   difficult   to  ob- 
tain, 14 

in  syphilis,  74 

of  heart  rare,  86 

there  is  no  established  stand- 
ard, 4 

radial  artery  and  vein,  62 
Nutmeg  liver,  107 


Ordinary  appearance  of  blood-vessels 

of  liver,    108 

of  blood-vessels  of  spleen,  116 
Organization  of  clot,  127 
Origin  of  disease  of  blood-vessels,  75 


Pathological  growths,  new  blood-ves- 
sels in,  24,  26 

Peculiarities  of  blood-vessels  of  heart, 
81 

Penetration  of  the  muscular  fibres  of 
the  heart  by  capillaries,  77,  82,  84 

Peripheral  and  central  parts  of  mus- 
cular fibres  different,  80 


INDEX 


135 


Perivascular  disease,  38,  51,  53,  59 

of  lung,  100,  102 

of  vein,  58 
tissue,  68,  118 

of  blood-vessels,  6 
Piersol,  80 

Pleura,  new  blood-vessels  in,  28,  30,  31 
Plicated  membrane,  7,  12,  42,  44,  54,  65, 
86,  127 

of  artery  of  kidney,  121 
Popliteal  artery,   il 

vein,   1 1 

Post-embryonic  development,  80 
Post-mortem  shrinkage,  7,  10,  12,  66 
Proliferation  of  intima  of  vein,  54,  62 
Pulp  of  spleen,  113 
Pulse,  radial,  61,  65 

R 

Radial  arteries  and  veins,  disease  of,  61 
from  a  case  of  meningitis, 

64 
artery,  13,  46 

hypertrophy  of  muscularis,  41 
thickening  of,  67 
pulse,  61,  65 
veins,  13,  50 

often  diseased,  65 
Ranvier,  80 
Rindfleisch,  23 

Rods  of  glass  in  blood-vessels  to  pre- 
vent shrinkage,  7,  10,  127 


Shrinkage  of  blood-vessels  at  death,  7, 

10 

of  capillaries,  post-mortem,  96 
post-mortem,  66 
Similar  lesions  in  different  diseases,  70, 

76 

Sinuses,  venous,  in  heart,  2,  77,  83,  84 
Sinus  venosus  of  heart,  14,  77 
Spinal  cord  and  brain,  blood-vessels  of, 

124 

artery  and  vein  from,  15 
Spleen,  blood-vessels  injected,  115 
blood-vessels  of,   113 
blood-vessels,  ordinary  appearance 
of,   116 


Spleen,  injected  capillaries  of,  20 

new  blood-vessels  in  capsule,  32 

veins  of,  116 
Structure  of  muscle,  78 

of  spleen,  113 

Subclavian  artery,  aneurism  of,  42 
Summary  of  description  of  blood-ves- 
sels of  heart,  87 
of  blood-vessels  of  lung,  104 

of  diseases  of  veins,  68 
Syphilis,  128 

blood-vessels  in,  69 

blood-vessels  in,  nearly  normal,  74 

of  vein,  52,  56 
Syphilitic  endarteritis,  38,  44 


Thickening  of  intima  due  to  clot-for- 
mation, 46 
of  radial  artery,  67 
of  veins,  50,  51,  52,  54,  58,  62 
Thick-walled  new  blood-vessels,  29 
Three  coats  of  blood-vessels,  6,  38,  43, 

53 
of  blood-vessels  of  spleen,  116, 

118 

of  veins  of  heart,  77 
Tissues  alike  in  embryos,  25,  56 
Tubercles  non-vascular,  33,  34,  35 
Tubercular    disease    of    blood-vessels, 

128 

Tuberculosis  and  giant  cells,  32 
blood-vessels  in,  69 
disease  of  radial  veins  in,  63 
Tunics  of  blood-vessels,  6,  38,  44,  53 

U 

Ulceration  of  arteries,  48 
Uncontracted  muscle,  80 


Vasa  vasorum,  n,  25,  70,  75 

Vein   composed   of   tissue    resembling 

epithelium,  60 
Veins,  coats  of,  51 

commonly  have  no  endothelial  lin- 
ing, 5 
disease  of,  37,  50 


i36 


INDEX 


Veins,  essentially  different  from  arte- 
ries, 2,  77 

fibrosis  of,  50,  51,  52,  53 

like  arteries,   73 

of  heart,  86 

of  meninges  more  diseased  than 
arteries,  71,  72 

of  spleen,  116 

syphilis  of,  52,  56 

their  anatomy  imperfectly  under- 
stood, 14 


Veins,  thickening  of,  50,  51,  52,  54,  58, 
62 

very  different  from  arteries,  5 
Vena  cava,  10,  14 
Venous  capillaries,  125 

sinuses  in  heart,  2,  77,  83,  84 
Venule  and  arteriole  of  ileum,  70 


Ziegler,  23,  29,  33 


WG500 
M512s 

1907 
Meigs,  Arthur  V. 

Stucy  of  the  human  blood-vessels 


MEDICAL  SCIENCES  LIBRARY 

UNIVERSITY  OF  CALIFORNIA,  IRVINE 

IRVINE,  CALIFORNIA  92664 


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